I carved my new filter out with an air tool with an abrasive cone, a little at a time until it fits. Then I put cling wrap (Saran wrap) over the carb area that you need to keep Proseal from sticking to. You need to tuck it into the corners around the accelerator pump protrusion so the Proseal will mold into the area nicely. Put the filter on with a gob of Proseal and secure it into its natural position. After it cures remove the filter and remove the cling wrap. Reassemble.
Rebuilt RV6A Flying!
EAA Ch. 292