Tried the sight glass from ZT. It's pretty simple, looks like a bleeder screw with a clear tube attached. Guess you could make one pretty easy. They have handy clips to hang over the vent on the lid. Just take out the drain plugs (3 screw SU's) and screw them in.

Marked the front bowl 22mm down from the top of the bowl, 22mm + 3mm from rim of lid to bottom of lid = 25mm like they say). The bottom of the lid as shown on FSM is not a good reference point since you can't see in with the lid on. My front carb was about 9mm low, figured it was low but worse than I thought. Finally got it right last night. Went back today and set the rear fuel level 23mm from bottom of lid or 20mm from the top ot the bowl. Nevermind the gasket thickness - close enough. Took a ride, Datsun seems to like it, but maybe set the mix again tomorrow.

The sight glass is also handy to drain out the bowl - makes it easier to rotate out and remove the lid/float assembly, something I had to do about 10 times.

Nice! Gonna have to try making a couple of those. Good thing to do while my manifolds are off.

I made mine by drilling a hole through a bolt with the proper threads for the bowl drain. I then shoved a nipple from a one man brake bleeder into it and ran the hose off of that. It works pretty well, but it doesnt make setting the float any less fiddly.

I was thinking of doing the bolt drilling thing, then silver solder a nipple into the hole. Should work.