The purpose of the mod on the diaphragm cover is to give the diaphragm its own air supply. The cowl pressure can be from heat or high air pressure or both resulting in a stalled pump. So soldering a fitting to the cover and running a tube out to another air source is a solution.
Also if your engine is cowled and its kind of tight then you can add a baffle between the carb and the muffler to block the radiant heat from the muffler. I made two for the P-38 and the diaphragm mod just to cover those bases. Plus I added large aluminum velocity stacks to increase carb cooling. Inside the cowls I baffled the engines too. Fully scale tight cowls and the engines run at 168F at idle. This all worst case scenario stuff but it works.
Ive run one 35 in a Zero and one In a TF Stinson and both run great without baffling or any mods.