Hi Jackdawack, Where do you live? Fuel can make huge difference. As Mick found I also find Tigers tend to like #3 slide better. The can also prefer .1065 needle jet. Amal sells this special size.
Overall E10 Unleaded fuel in USA, motor likes about 5% richer jetting across the board.
You have premier. Good! They work great. .019 pilot (idle) jet is correct & works better than .017 like old carb had. Many internal changes in premier so they require different settings.
Float setting for premier is very different. Just above gasket surface & level. This is correct! If you lowered float level, raise it back up. then road test before moving on.
As was stated, timing is critical. It must be checked. You may find bike works better 3/32" retarded. I'd do that. I do that on my bike as well as others I tune. Looking at pointer in timing cover. Hash mark on rotor will end up 3/32" closer to front wheel from pointer.
On occasion the rotor alloy can slip on the steel center hub. That will throw timing marks off. Good plan to verify the rotor hash & pointer with TDC tool in 38b slot in flywheel. Note position & compensate with the hash/pointer relationship. Timing is very important. Even left to right is important.
Well serviced points are very reliable & allow starting with dead battery. Key work: Well serviced. Taking half a turn of end of advance spring & smoothing any flat spot worn in fly weights is good idea. Smooths idle & just above idle.
On the other hand, Boyer has a much more desirable advance curve. Gives perfect timing left to right. Tends to reduce the shake in motor just off idle that points AAU may cause. The down side of Boyer or any other electronic ignition is low voltage will make impossible or hard to start. So if you choose electronic be sure your battery & charging system is always well maintained & electrical output is to specs. In every case poor charging system is no good, so in many owner's mind, electronics advantages far out weigh the negative of low volts. The single biggest advantage of electronic ignition is the desirable advance curve with modern fuel. Substantially reduces pinging & holed pistons, but if mixture or timing is not properly set it cannot compensate for that.
Regarding getting slide & all the other mixtures correct, it will take some practice, experiments & very important to mark your grip in 1/8s. Use masking tape on grip & throttle housing. Take up cable slack very gently, twisting grip. Mark that zero. Turn to full throttle. Verify slide is full up. Mark as full. Then divide marks in halves. The eye can find center points fairly well. Use dividers if/as needed. Be accurate on marks! Adjust throttle cable, idle rpm as needed before marking grip.
Often needle will want full up, meaning clip on bottom groove. Main jet one size lower than 8 stroking. This will go a long way in preventing melted pistons on hot days up hills. Remember unlead fuel plug readings are really tricky. Not like '60s & '70s. When it looks a little too rich is probably just right. However, go more by road tests than plug reading.
You'll soon learn how little throttle is used. Seldom more than 1/16-1/8. The needle will wear flat spot here. That skew mixture into being rich at worn point. So watch out for that. If you lean it there to just right, it defaults to lean when jet is on unworn part of needle. If in doubt replace needle & needle jet. Jet wears oval. Even .0005" wear is a decided change in mixture. Sometimes.... a worn jet with new needle is just right. Trial & error. Try each one & see.
Again, worn needle is always problematic.
Slide size is found at snap throttle test. Sometimes (often??) you'll be right between #3 & 3-1/2 cutaway. Default to richer #3 if you find this.
Since bike runs good you're not far off. Start with main jet then work with needle clip, then slide. Your pilot get of .019 is good. It will have 3 small rings machined into the silver tip of jet.
Print the road test part of John Healy's tuning guide. Put it in your pocket, you'll need to memorize it.
8 stroking is an odd misfire that sounds like ah ah ah ah ah at full or just shy of full throttle. Backing off goes away. cranking on comes back. High gear 65 mph up a moderate hill or head wind is easiest.
To rich if slide can 8 stroke on snap throttle. But you need to really listen & know what 8 stroke sounds/feels like.
Too lean the bike will gain very slight power when you back off throttle, like 1/32 turn. Very hard to feel until you understand it. Easy to smoke piston when lean. Better to go too rich, then back off going leaner a little at a time.
Again start with main jet. If main jet is not right, it can/will confuse the needle clip position.
I don't know what air filter or exhaust you are using. That will make a difference in mixture.
I've chased my tail for days (a few months actually) with paper elements in air filter. Don't use them. The original type wire/gauze is better. They clean fine & don't mess with air flow at different RPM. Or should I say, Triumph must have designed carbs to complement them.
Find a road test route that has all the conditions of testing you need. Use same route every time. Then you'll feel changes much more readily. It takes a good 10-15 miles to get motor/carb to minimum temp to set mixtures. After 50-60 miles you may need to trim idle mixture idle rpm. You'll learn to find the happy medium.
There is no provision for cold fast idle, so motor will not idle on cold mornings & in hot weather take a good 2-3 miles before idle is to be trusted. If bike runs really well cold, idle mixture is too rich. Some Electronic ignition has idle stabilization by changing idle timing. They idle great no matter what unless really cold like <40f. That's another story.
What sucks about our bikes is you must remove carb to access slide. Makes the job very time consuming. Just have to accept that. If you have stock air filter, the boot is a pain. 750 Tiger is worse with offset boot hole.
Here's the tuning guide. NOTE the float level of .080" is for older carbs, NOT premier. They demand much higher to achieve the correct liquid level in bowl.
Don