I think if you're looking for 6 years, you're looking at 3 years of his prime FA years and that's going to cost you. Considering SP of his caliber are getting $20-25MM year, I'd ask for something like:
2013: $4MM
2014: $9MM
2015: $14MM
2016: $16MM
2017: $18MM
2018: $20MM
So something like $80MM plus some incentives. IF you just take him to arb for 3 years and stays healthy, he'd be in line for something like $25MM/yr in 2016-18.
I think a more likely scenario is simply getting some certainty through his arb years for ~$25MM. Cueto's deal is not a great baseline because he didn't have the track record of excellence that Latos has and we're further in to an era where the TV money has gotten silly.