I have been using the flanged Smoke Tech prepunched cartos for a year in my tanks. I almost never get to use one till it dies because I drop my Provari nearly every day and the 2 piece assembly of the Smoke Techs makes them come apart at the flange. I love standard boges and so after hundreds of dollars in expensive prepunched Smoke Techs broken I decided to have my hubby slot some standard boges for me. They work great with two slots but the problem is that they are tearing up my O rings when the slots go threw. Today I received a carto punch and it works but I need 2 holes and it distorts the carto so much that the hulk would be lucky to get them past the now new o rings. Does anyone have any advice? I know people do this stuff with success every day so what is the solution? My husband is out in the garage as I type trying to smooth down the edges of the slots on a carto. I cannot try it out now till I empty a tank as the Two I have cut down for standard Boges are full.