Just my "opinion" here BUT I would look to your "Zenith" carburetor first and make sure that it is set correctly, the proper float level is set etc etc. IF you check out Renner's Corner and what it takes to properly set the float and fuel flow you will see!!! They are not as simple to get right as many think!!! As you stated, running rich and that is the main feed source for that issue!!!! I have just recently gone down this particular rabbit whole....and have 4 Zeniths done and ready SO I have most recent experience on them!!!! Once you got the Zenith right, clean your current plugs and see how it runs
FOR your 32, the "raised" Zenith is what you should have, IF its raised with a cast "3400" (I believe is the number) that is a post 34/Service replacement. IF you have a "late" 32 and an "indent" Zenith, you could continue to use that which carried into the 33 and 34 4cyl's. IF you are going for "proper authenticity" 32 carburetor is your goal?
AGAIN, just my opinion!!!