I'd actually use this (OMG, it's not OCN)
, that's what followed on my Mint 12 install just a few weeks ago. On this I really only used the basic guide and setup auto start at boot in the background with rc.local
as per post #6 in that guide.
If your OSes can both access a partition, you may
be able to put FAH there and have them both work on the same WU and as both are Linux they use the same Fah-core I think it would be fine. But I've never tested this myself and there is a possibility that it will work fine to fold, but you loose bonus points if you download the WU while in one Mint and uploads in Debian (but might be fine, can't really say).
Otherwise you'll have to do the setup twice, but as the SMP WU have a Quick Return Bonus system you'll loose points on both if you switch back and forth. Maybe just set up FAH on your main OS (if you have one), if he above doesn't work.
The 4250 will be great...for displaying your desktop etc. There isn't any way that could fold under Linux afaik, even if it could there wouldn't be much point as it's pretty slow and would suck to many CPU cycles.