I think the 120s will be a bit rich unless you are also opening up the intake side with something like a K&N air filter and possibly removing the snorkel and putting on a bellmouth. If you open up the end (exhaust), you need to open up the beginning (main jet and air intake). Just order the jets from NewBonnieville.com. While you're at it order the D tool for adjusting you idle mix (pilot) screw. You need the D tool to do that adjustment. You also really need to get the replacement socket head carb bolts. There is no point going to the trouble of getting the obnoxious phillips head bolts off (four on the bottom/float bowl and four on the top of each carb) if you're not going to replace them with these socket head bolts. It's standard practice to do this when you do your first rejetting. Just check first to make sure that the old owner didn't already do it.
You can go to the Jenks site, click on link, and print out the whole Jenks Guide from the pdf.
Regarding sealant for the pipes, I used Permatex red High-Temp RTV silicone for my Hydes.
Regarding a manometer, go to the Carb synch thread listed below for DIY links, Motion Pro mercury carb synchronizer link, Morgan CarbTune link. If you want a Motion Pro mercury synchronizer, NewBonneville carries that as well.
Carb Jets at NewBonnieville
D Tool at NewBonnieville
Socket Head Replacement Carb Bolts
Carb synch thread