I don't use MakerWare myself so I don't know what the pitfalls might be. But for the time being, you should be able to do much of your slicing and x3g generation from MW. You need RepG to download the firmware, for initial bot setup (RepG sends data to the bot over USB as part of configuring the bot the first time), and you need to use RepG if you later want to change any of the bots "on board preferences" from your computer (as opposed to using the LCD display).
For further questions, you'd be better served to join the jetty-firmware group at http://groups.google.comgroups.google.com.
As to donations, you can send me a private message and I'll send you my paypal address. Jetty and I split them 50/50 and use the funds for purchasing filament and other consumables or parts we use in doing our firmware testing.