With a WSM on a short action, the problem you run into with the big, heavy, and long 208 and 210 bullets is overall length. On a short action, you have about 2.880" max length to work with. If you seat a 208 A-max even with case mouth and the ogive of the bullet, you are already at 2.877" (see math below). The 210 VLD gives you a little more room, but not much. But, the bullet is seated so deep into the case, it eats up powder capacity. This will reduce your speeds quite a bit. Most shooters who run a WSM case with the heavy bullets put it on a long action, and throat the chamber long to seat the heavy bullets out far and gain powder capacity. If you just want to punch paper out to 1K, a 210 VLD may work best. The gunsmith will need to use a zero throat reamer, or specially cut the throat to get the 210 on the lands at your max length. It can be done.
The 300 WSM was designed to duplicate the speeds of the 300 WM with a 150 grain bullet. It gets pretty close to this by efficiency of case design, and a fat, compressed powder column. Once you start increasing the bullet weight, the WSM begins to keep up less and less with the Win Mag. The heavier you go with the WSM, the more velocity you will lose to the WM. Generally, the Win Mag is faster by about 100-150 fps over the WSM. For the reasons above, is why I'm a fan of the 300 Win Mag. If I had only 1 caliber to chose, a 300 Win Mag would be it. I'm running a 225 Hornady BTHP at 2900+ fps suppressed, and ~2850 fps unsuppressed. A 190 grain in the WM is generally 3000-3050 fps.
300 WSM case length- 2.100"
208 A-max ogive to tip length- .777"
210 VLD- ogive length- .708"