What about trying this Dubbin?
I have a 396 and live in Ohio. MARCS came preprogrammed with the radio. Now granted, I didnt check to make sure EVERY single CC is in there, but I just left them all in there. (with the exeption of a few CC's that were also TRS voice channels in my area) I have locked out the distant posts that arent near me and added the talk groups that are closest to me, most of which were already there.
Whenever I travel around town, or even around Ohio, the 396 changes from one CC to the next as I move about. If I happen to go up your way, I will unlock the District 1 TG's and listen in. Same as if I went to Columbus or Cleveland.
In a way, Im letting the 396 due the same thing the MARCS radios do-- search for the best CC and monitor from there. If Im in the boonies, I can always set it to search instead of scan. One could argue to just leave it on search, but I prefer to unlock the TG's for the area Im entering and lock out the TG's from the area I left, when Im on the move. If you leave it on search, you will have to research the TG, and that's too much looking in books or papers while the car is moving, even if I am riding along.
I always have more TG's to load, but I dont think I will break 200.
I'm not sure if this is what you were asking or not, so dont pounce too hard. To me, my setup seems to be the best way to monitor a system like MARCS. The scanner switches between the CC's very well, and the only areas I have trouble are the fringes between the CC's, but most of the time Im not even using an external antenna.
Hope this can be useful for you-