I ensure that wheels built with ZTR rims have spoke tensions lower than I would use on other rims. The actual tension is a little higher than the recommended tensions from NoTubes – based on the readings given out by my 2 tensiometers (soon to be 3).
Remember I supply wheels to paying customers, I want to ensure everything is as perfect as I can make it. The last thing I want is warranty claims on failed rims. This approach has served me well, I’ve built lots of ZTR rims and everything worked perfect and I’ve adopted the same strategy on my latest ZTR activity.
Your situation is different. If you get things wrong tension-wise the only thing that’s going to happen is that your rim may fail and you have to buy another rim.
Here’s what I would do in your situation. Crank up the tension a little more (but less than a normal build). Ride and see what happens, repeat as necessary. It’s part of your wheelbuilding learning and as a wheelbuilder you’ll find it interesting.
Flow is a strong rim so I don’t see much possibility of it going pear shaped. 355 and Olympic need more care.
The mode of failure is going to be fatigue and that depends on how many miles the wheels get, so people with super tight ZTR’s with no failure may not be riding them much. There wont be static failure because I’ve tightened a ZTR Olympic to 2000N (not ridden it, cosmetic second that I experimented on).
Roger