1984 B2000 SE-5

I've been messing with the carb for the past couple months. I've gotten it to the point where it reliably doesn't starve or flood, but the float is still set way too high. Problem is, there's no external adjustment. I have to take apart the bowl every time I have to adjust the float, and I only know if it's right once I've run the engine for a while. Anyone know of a way to calibrate it, so I can stop wasting gas like this?

I've seen new ones around the internet, but the packaging on em says you need to adjust them as you install them.