if you have a foot switch for the rm4,plug the midi thru on the rm4 to the T C.when u switch channels on the rm4 the T C will change,the only thing you will have to figure out is when the rm4 changes what program comes up on the TC.i think it has 4 midi program numbers assigned on the(1 per ch) rm4.then you will have to change (midi mapping)the TC program number you want to match the rm4 channel. Edit the TC by now changing the program number to the one you want and save it,this should map them together.my rt2/50 uses ch 1 midi #87 ch2 midi#88 ch3 midi89.hope this helps,it is not as confusing as i have made it sound and if the RM50 and RM100 have midi in and thru it should be the same.
Also if you get the TC and it has a midi pedal you can use it going midi out on your TC into the RM4,RM50,RM100.push the pedal,bring up your tc effect you want and map it with the RM.best thing to do is use the 1-4 on the pedal for any of your main sounds (rhythm,lead) then use the other numbers on the pedal for you effects ex.ch 1 rhythm clean w/ tc reverb ,ch2 rhythm crunch w/ tc reverb,ch3 lead w/ tc reverb ch 4 lead w/tc reverb then pedal button #5 say for pink floyd sound have it bring up ch 3 on the RM and delay w/TC. Pedal button #6 ch1 clean w/chorus on the tc.there are many combinations, make it easy so you dont have to tap dance on pedals. i have my pedals rack mounted and 2 gcx switchers,i controll any number of pedal ,amp switching ,which preamp or amp and midi rack gear with the push of one button on my ground controll unit.