It's a finicky process. Took me about 2 hours per rim to true the wheels on my /5 for the first time.
I would attach a dial indicator to your setup. It'll make truing the side-to-side and up-and-down runout of the rim much easier.
Also, you need to measure the rim offset when truing /5 wheels. This will ensure both wheels are inline, when mounted on the bike, and adequately center between the front forks and rear swingarm. To determine the offset, just place a long straightedge on the drum side and use a caliper to measure the distance between the straightedge and rim. Whomever trues your wheels will need the below reference information.
Hope this helps and keep up the great work!
That's some good info, elite-less. I need to have my wheels laced and trued. The shop nearest me that trues wheels is a motorcycle racing shop. Awesome guys, but they're not too concerned with Airhead arcana. The last time I was in they spent a good 30 minutes telling me why I should ditch the stock wheels on my /5 and use 17-inch rims instead. If I end up using them to do my wheel-building, at the very least I know I can hand them that sheet and ask them to follow it to the letter.
Let us know how the Triumph guy does. Did you give him the sheet?