i think a lot depends on your league scoring
take the tier 1 WR if hes there then take your #2RB later.
IMO these guys (Tier 4 RB (top Tier 4) - Lynch, A.Green, Caddy, J.Lewis) are pretty solid and reliable, but these (Tier 3 RB (lower Tier 3) - Benson?, Jacobs, A.Peterson) all are a little risky.
You're getting better value with the tier 1 WR.