24p and 60p on the same timeline in FCP7

I'm wondering if others have experience editing 24p and 60p on the same timeline(FCP7)? In my case, it will be 1080p @ 24fps and 720p @60fps. (I'm not worried about the 1080v720 issue though, I don't see that as a problem)

I'm organizing a shoot of a live event. I would like the end result to be 24p (will definitely be outputting to web; also perhaps a 720p BluRay; and a few copies of DVD). But I know I want at least one camera shooting 60fps so I can get the look of overcrank for some of it. I know FCP7 doesn't make this easy the way Premiere does (slowing down a 60fps clip on a 24 timeline just duplicates frames...sadly), but I can use Cinema Tools to turn the 60p into 24p at 40% speed. Not ideal, but I'd rather cut in FCP7 in spite of this hit to the workflow.

I have put 24p and 60p on the same FCP7 timeline on a few rare occassions and saw no ill effects. I am wondering if others have done it for larger projects or have larger experience with that and can share if that's an OK practice, or if I'm better off having both cameras shoot 60p - and perhaps simply converting the final output to 24p in encoding.

I appreciate any thoughts on the matter, thanks!