GT2 is the most forgiving of the new lineup.
The GT3 can be tailored via the sliding weight/sure-fit hosel, and is a great mid-tier choice, and the GT4 is a low spinning monster, but requires pretty consistent ball striking.

Of course, getting fit is the proper answer, but if consistency of strike is an issue, I'd say the GT2 is your safest bet.
For me personally, the GT3 is like Goldilocks' porridge. Just right amount of spin, and workability/forgiveness,
although it is always fun to try and blast bombs with the 4 haha

GT2 or TSR2 will spin a bit more (helps ball go straighter) and is generally slightly more forgiving and straighter than the 3 series models. Might be worth trying.