What's the best way to mix Canon HF100 and Nikon D90 footage for output to DVD Video?

Should I keep the D90 at 24p and shoot the HF100 at 24p to match, shoot the D90 at 24p and HF100 at 60i and match in post, something else?

Or is it just a very poor idea to mix the two in the first place?

Thanks,
-Joel