Six Pack Carb Fuel Leak

I agree that 7 psi is pushing it. 3.5 to 4.5 would be good. 6 max.

That doesn't relate to external leaking out the bottom.
If they leak until the bowls are literally empty, on the outboard, the only thing is can be is the bowl gasket or the lower screw washers.
I realize that is a PIA to change.

The blue Holley gaskets are good. I touch them with a drop of WD40 to somewhat kill the sticky. That makes removing them easier.
For carbs where you're opening them up a lot, gaskets made of MP (?) material are probably better. I've got some of them in a carb right now.
For the bowl screws I use and reuse the black ones in the Holley kits.
Urich's 4150/4160 Carb Book shows fuel bowl screws should be torqued to 50 in lbs. This looks right.
I'll try to corroborate that later. I know there was one torque spec that's wrong in one of the books.