Sorry my OU fan, you probably hurt yourself by making this choice. Very rarely do folks who go to Vance end up staying with their class all the way through T-1s. I've heard maybe one person per year gets TACAMO out of Vance, and some years no one.
I can tell you from experience, walking into the squadron spaces of the T-37 squadrons was like walking into a morg, the scent of misery, dissapointment, and death was very present. Probably 90% of my AF classmates who went through 37s hated life while going through them (the other 10% didn't care). They regularly told me how the IPs treated them like dirt, worse than thrid class people. The days were 12 hours everyday except for like the last 3 weeks. Forget about having fun while flying, it apparently doesn't happen. Even their cross countries suck. On mine in 34s, I went to Vegas and had a blast. The instructors we went with bought us a $50 dinner plus drinks, went gambling with us, heck even tried to get the ladies for us studs. Forget about that in 37s, your XC is 3 straight days of flying, and the days will be close to 12 hours long, and oh yeah, there is a 600 mile ring around Vance you have to stay within.
There are no watches as you would know them at Vance. They do more formation flying, a skill which will be absolutely usless to you in TACAMO. I think the total number of flight hours is about the same as 34s. The other thing is, you will not start up right away at Vance. You will have to wait till your class start date comes around and then do their version of API. I can't tell you how long the wait will be from when you arrive to when you start.
My only advice, if you can reverse this decision and wait for your Whiting spot I truly believe you will have a better chance of getting TACAMO. Also, word on the street is TACAMO is going down to only 18 slots per year, so if this is accurate that reduces your chances by 25% right then and there. I wish you the best of luck.