I finally completed my 70M team. I didn't even try multiple combinations. Once I found something that worked (i.e., that fit), that was it.
I found this theme very difficult. The biggest issue was the narrow $2 million range to try and squeeze in the right combination of players from a selected team. I often found a team would be at $17 million and the only additional player worth adding was over $3M. Or I found a team with five $4M+ players worth adding.... which means I'm at $16M or over $20M. I think a $4M range (i.e., $16-20M) would have made things a little more manageable.
Oh, and I initially forgot about the full/partial rule, and of course, my first pass had a player with a combined season on the roster. Doh!
I'm assuming others had trouble as well.