Hi Shane,
To get field flattener, OAG, DSLR working together stable and with correct distances could be very tricky. Hard to find the correct parts.
I have written down how I did it on my refractor, part of it will be the same for you:
http://astrofriend.eu/astronomy/proj...refractor.html
Biggest problem was to control the vignetting to not be too big.
/Lars