[carmine]

A zero bypass valve will most defanetly biuld up fuel pressure in the pump chamber caused buy heating up of the carb body and expanding the fuel which has no place to escape except out the pump jets.

The larger the bypass valve # the more of the pressure biuld up will divert back to the main float chamber, Thus allowing less fuel out the pump jets during pressure build up from shut down heat sink of carb body.

Yes your carb body will be cool to the touch after shut down.
Check how hot they are 10 minutes later.

The pump Jets are not affected by the angle the carbs are on because they are fed by an inlet located at the bottom of the main float chamber.