2.710 is SAAMI maximum for the 243 Winchester. Trim length, case length and OAL is the same for the Winchester and the AI version. Here is an article with cartridge drawings of both. http://www.6mmbr.com/243win.html
Barnes lists the 80 TTSX OAL data as 2.610. Hodgdon lists the 80 GMX load data at 2.610, and the 85 TSX at 2.620. Even the 100 grain BTSP they show at 2.650.
I do know in some of my stuff, the Vmax bullets have a different ogive that results in needing to seat deeper than other bullets of the same weight, and I think that 87 was one of them. I don't think you will have a problem with the 80 TTSX at a good length. On mine, if I remember correctly, the neck of the case is between the first and second groove from the front on the 80 TTSX. The Barnes factory loads are crimped right into the first groove.
I just looked on a few sites, and many guys are loading the 87 VMAX at 2.650-2.665, so that throat might not be that short after all. The factory load is another story. Not sure on that one.
