I think you just take the tried and true "best player available," factoring in you own +/-'s and appetite for risk/reward (and potential injury guys).
In looking at you picks (#15, #18, #47, #50, #79, #82), I'm trying to figure out the best spot to grab an top SP. I think your first two picks should net you some great hitters, especially if some of the top SPs go ahead of you. Your 3rd/4th rounders could get you a Wainwright/Greinke/Gonzalez w/o reaching, and a Weaver/Hamels if you get really lucky.
Definitely hitter in rds 1/2 and you could still net a nice #1 SP in the 3rd or 4th.
Tulo/Longora could be a great duo, but you're going to have to embrace some serous injury risk that early. If it pans out you could net two top-10 players by season's end, but the downside is pretty significant for a players that early in the draft, hence their potential undervaluation.
Definitely have options.