Most Marlins have a SAAMI throat (Winchesters, on the other hand, tend to have long non-SAAMI throats. I don't know about Browning throats). Here is the SAAMI spec for the 32-20. It calls for a max nose length of 0.275" and no throat to speak of.
Here is a suggested design that should work with the SAAMI chamber. I have no way of testing this design, and I certainly can't claim that it is optimal, I'm just saying it's compatible with the SAAMI specs.
The only sure way to know what will work in your lever gun is to make a throat impression and experiment with dummy cartridges of various COL's and nose configurations.