Some drum heads have a built-in warmness and others are more bright. If your Pro M's are Birch, then the G2's are gonna be really bright, if it were maple, the G2's would sound slightly warmer, but the G2's themselves are inherently bright...
For a warmer and somewhat darker sound, I recommend getting away from the G2 coated heads on toms, especially the floor toms. The coated heads tend to give you more "stick" sound--the slap you hear when you strike the drum with a stick. They also resonate more and tend to have more of that "ring" sound you are trying to get rid of with your abundance of moon gel...
Changing heads to a hydraulic 2-ply clear will warm-up the sound more and the lack of a coating provides less of a slap or "stick" sound in the primary
attack. If you want to really change the sound try going with the ebony or dark colored hydraulic 2-ply heads--they will make the sound even more warm and dry with very little overtone. Less moon gel is necessary...
FIRST, see if you can find some drums with hydraulic 2-ply heads and ebony hydraulic 2-plys and see how you like the sound. Hopefully there's a drum shop near you that has some you can dink with...