Superflex Keeper help

Hey Footclan! In a 10 man, full PPR, 4 keeper super flex that also starts 3 wrs instead of 2. You can keep a player the round they were drafted for life. 3 locked in, need help with number 4.
Locked in:
1 L. Bell 4th round
2 D. Freeman 16th round
3 J. Nelson 1st round
4 ?
Kirk Cousins in the 10th or Marty McBry in the 15th?

Cousins in the 10th in a Super flex? Yes, please.