There are at least six reasonable ways to play drafting at the 12-13 turn, assuming a start 2 RB, 3 WR league. I have listed them in the order of most conservative to least conservative below:
1. RB-RB, WR-RB Offers the best opportunity to have a strong running game
2. RB-WR, RB-RB Should get a top 10-12 RB, top 3 WR and a good shot at a decent RB2
3. RB-RB, WR-WR Potentially two top 12 RB and two top 12 WR
4. RB-WR, RB-WR The most balanced approach, should have four quality starters
5. RB-WR, WR-WR Rolling the dice on finding a serviceable RB2 later
6. WR-WR, RB-WR WR overload, going against the grain, but tough uphill battle on RBs
I would try to use approach #3 or #4 in most leagues, but a lot depends on the talent available, the league in which I am competing, and the flow of the draft.
In one of my leagues, only half of the teams have shark owners while another half are unpredictable and/or less competitive on average. In this league, I will consider becoming more conservative as I expect to be among the leaders as long as I don't make multiple mistakes. So maybe I choose approach #2 or even #1.
In another league, competition is extremely close every year, so I just may be more aggressive, going against the grain, trying to give myself an edge. So perhaps #5 would enter consideration although probably not #6. If I use this approach, then come rounds 5-6 I'll be looking to snag a pair of players like Addai/Rhodes or TENN or JAX or SF. I know I'll be likely taking a hit at RB2, but if my RB committee works out, I'll be hard to beat considering my strength at WR. Even if RB2 flops, perhaps my WR strength will cancel out my RB weakness.
Looking at #5 a little bit deeper, 35 picks will have occurred before team 12 gets their 3rd rounder. If each other teams has drafted 2 RBs, and at least Manning and Gates are gone, then at most 10 WRs will have been drafted. So theoretically, team 12 could have a top 10-12 RB (drafted at the first turn) along with a top 3 WR plus two more top 12 WR.
If you choose #4, then you end up with a top 10-12 RB and a top 3 WR from the first turn, then likely RB 24 or so along with a top 12 WR. Your next WR probably fits anywhere between WR 20 and WR 25. So would you rather have:
#4: RB 10, RB 24, WR 3, WR 11, WR 24
or
#5: RB 10, RB 30, WR3, WR11, WR12
Considering that the “RB30” could be a team or relay RB with the potential to hit the top 20 as the situation resolves, I am tempted to go with approach #5. Risky, yes. But there's a chance to be dominant if the RB2 works out sometime during the year.