Have you taken a diagnostic? If so, what was it? I feel like the answer is Ultimate plus regardless due to the amount of material you will have. It’s the best out there as far as bang for your buck, IMO.
The difference between my diagnostic and current PT score is 20 points (157 - 177.) I've been at it about 20-30 hours a week for nearly 11 months. You can surpass your goal with effort.
I'd say if you're scoring 177+ on your PT's then go for it! One of my friends scored a 172 and then studied a bit more and got a 179. He's in at Yale now.
My target score was 180. I never thought I should ever shoot for anything less. I never reached it on any prep test but I hit 177 after about 10 months.
I am also willing to mentor one person for free. Highest prep test: 177. Two-month average when finished studying: 172. Real life scores: 164/165. School starting in fall 2020: William & Mary.