Though i'm sure it would work, I don't believe that it would be the best set up. Taking apart the condenser every time you want to change the contrast isn't exactly promoting a fun darkroom experience. If you've got the smaller drawer that's used for the red filter, i'd say use that. I cut filters down to fit in mine for both my 23c and my 45m, they both have the same size drawer. That said though, if you did have the filter drawer up top, that is a better set up. The other option would be to get an under-lens set up, but i personally am not a fan of that. Otherwise look around for that condenser house with the drawer. I'd offer mine up, but it's my back up in case my cold light head dies, or for when i do use condensed light.
The other option would be to DIY a filter drawer, if you're handy...