I regularly use the pass button to light both filaments in the front bulb, for shortish (a few minutes) periods of time on my old Dominator. Gives you a far better spread of light on an unlit country road (a lot up here). Doesn't worry it, done it for years, doesn't even blow the bulb surprisingly.
Now, I've put a 100/80 bulb in the front of the TA and have done the same for a few weeks, seems fine. That must be drawing some current though.
Reckon the wires are up to it? I think I'll go out to the garage and keep the pass light pressed and feel actually how hot the wires get. The fuse should blow before it melts the wires though, surely?