My plans have changed regarding 4*. I'd still prefer to have 2 high level dupes, than a higher level champion, but that would be way too far off in the future, due to scarcity of 4* covers. I'm going to max Cyclops and Red Hulk.... After I get these Cyclops and Red Hulk maxed and champed, I'll go for round 2 of championing 3*. After that, I'll consider maxing more 4* or going for some 3*. X-23 and GR are at 160, TAH at 131, Venom and Miles only at 70, so they might get taken to 200, but there's no priority for them. All other 4* are at 200.
The 4* dupes that I do plan to level, I will roster a 3rd of that character. 4* dupes will have the build that I'd choose if I only had 1 of that character. The 3rd will just sit at 70 collecting whatever covers drop (EDIT - will have the 3rd spec'd to preferred build too, will sell covers that are extra). Dupes for me, are mainly healthpack savers, and because it pains me to sell 4* covers. Sold a Thing Yellow and Carnage black, since my dupes already have 3 of each.
Current plan is putting all into then