Thanks to everyone who has posted useful information about changing fork seals. I have benefited from your collective wisdom, and have now been able to change my leaky fork seal. As advised, I took 2000 grit wet/dry paper to the tubes to smooth out the tiny rock dings, and now things are totally dry.
I thought you might be interested in how I safely raised the bike so that I could get the forks off. I put up some bicycle hooks from Home Depot into the garage ceiling, and ran some tie-downs around the frame...
...after I lifed the bike with my cheapo lift ($39 after rebate from PepBoys), using a piece of 2x8 leftover lumber to clear the pipes...
Because I'm too cheap to buy the Triumph tool, I used the end of a caulk tube and a 1.5 inch PVC pipe connector to slide down over the tubes to install the seal...
Now that I've added fork protectors, I hope to be happily leak-free for many miles to come.
So if you're thinking about changing your seals, go for it! It's really not that hard, and you'll be glad you did. Just don't forget to get those tubes silky smooth so the little dings that did the damage in the first place won't tear up your new seals. The Haynes manual is very helpful for this job, so I'd recommend that get one if you don't have it yet.
Cheers :-D