Lexrst wrote:

Is there a way to do that via the GUI or am I going to need to do some sysex work (of which I know nothing)?

You simply have to send Program Change messages to the channels you wish to change. I do not know if you can do this real-time in Cakewalk but in Cubase you can.
But I'm sure you can set permanent Program Change messages in midi tracks in any DAW (including CakeWalk). Also it's better since this way Program Change messages are saved with your project. SysEx messages are only required if you want to change the default MT-32/GM sound banks. For the predefined 128 MT-32/GM instruments no SysEx messages are required.
BTW there is a better topic discussing Munt VSTi related issues here:
Falcosoft Soundfont Midi Player + Munt VSTi + BassMidi VSTi
I only found your post accidentally.

Gotcha - I will investigate how to send a program change in Cakewalk. Thanks for pointing me in the right direction!

Thanks to your information, I figured out how to insert a program change into Cakewalk. I greatly appreciate your assistance!