Need more info.
-Is the 240 now two 120s in parallel nailed flat to the roof? or can they be tilted?
-will the two 120s be in series with the new MPPT (which affects options for how the 100 can be integrated)
-how many amps (size) is the PWM controller? (can you just add the 100 to that--very simple then)
-what do you expect to gain from changing the 240 to MPPT?
-how far away from the rig will you be deploying the suitcase set?
-100w will do about 6.2amps aimed at high sun. Why is that considered "huge?" What do you get now with the 240 as is?
There are too many ways to connect it all to try suggest any one way without knowing more of the situation.
