Not that any two projects are alike, but I often find myself asking in these situations, what is the end game? Where is this footage actually going to be viewed and then based on that I decide how important certain quality issues are. In most situations for me the biggest concern is staying in sync at the lowest cost. If I have lots of monitors playing back content spread over them I want it to be in sync way more than I am concerned with how high quality the codec is. Viewing distance and screen size are always in my mind when I consider these types of things. I may not be a video-phile but I doubt I could tell the difference between a 422 HQ and 422 proxy on a 50' plasma at 20' maybe it's just me.
But I feel like I am missing something, if you are shooting in red epic, which could be 5120 x 2700 and you want to have 3 x 1080 you would actually be scaling up to fit it horizontally while at the same time losing almost half your resolution vertically. Not all bad since your pixels will be close to 1:1 in the area you want. If it were me, I would shoot at the highest quality possible, edit at the highest quality possible, render out a full size 444 and then from that you can make lower quality slices if need be but you always have a high quality source file to work from on other projects. It doesn't take that long to do a re-render at a lower quality but you will regret it if you do the whole thing in proxy from the get go and later want to stretch the whole thing over 6 monitors instead of 3 one day.... but then again that depends on whether or not you think you might try that.