Simply put, we're making a sports doc. We're recording the broadcast feeds into a Pix 240i, and shooting everything else (game footage, interviews, etc) on Alexa at 23.98. This will be a completely tapless workflow: Link to AMA volumes, transcode to 14:1, then relink later for upres. My question is, which project type will yield the best results? 23.98 project and let avid convert the game feeds, or 29.97 and let avid convert everything else? Another option is to have the Pix covert 1080i 59.94 feed to 1080p 23.98 on the fly. I'm getting some pushback on that from people who are concerned that there will be motion artifacts.

EDIT: The entire show has to be delivered at 1080i 59.94, so if we cut in 23.98 the idea is to use a Teranex converter on output to get 1080i. It's not dawning on me that if we cut in 23.98, the game footage will essentially be converted twice.  

No group / multicam clips? It is not supported in a mixed format workflow.

Generally, your edit frame rate is dictated by the delivery format, this case 29.97. Bringing in 23.976 footage in a 29.97 project will result in a 2:3 pulldown effect. This means your 23.976 will look no different than watching HBO. HBO masters in 23.976 but broadcasts in 29.97 via 2:3 pulldown.

29.97 converted to 23.976 is not as fluid as traditional 23.976 to 29.97. You make it worse by going 29.97 to 23.976 then back again to 29.97. That process will create interpolated frames. The 29.97 deliverable will contain interpolated frames even on 29.97 footage. What was thrown away in the 29.97->23.976 conversion will not be recovered.