if you were to run either one, i think it would be the pistol without a doubt.
The read-option requires a legitimate running threat at the quarterback position and while i love tannehill's abilities, they're not sufficient here.
I do like tannehill in a pistol offence though, he will not figure as a main threat on the ground, but defences would have to take in consideration his talent in those rollout/bootlegs/playaction/etc. plays. Tannehill is very good outside the pocket, either throwing or picking up a few yards on the ground...
with all that being said, I think the spread offence would be the best for him... (think of new england) ... he just needs that deep WR threat and I think he'd be a beast in a similar offence