I don't know off-hand exactly how to size the bracelet for your wrist, but you should be able to get an acceptable fit. Some owners have found it difficult to get a
perfect fit for a couple of reasons: 1) the Speedmaster Pro bracelet does not come with half-links, and each individual removable link is fairly long, so there is a fairly large change in how the watch fits for each link that's removed/added, and 2) the clasp has only a very small amount of micro-adjustment available.
There is a solution to issue #2 above, which is to install the micro-adjustable clasp that comes standard on some of Omega's divers. Quite a few TRF members have done this and been very pleased with it (including me). Here's a TRF thread with lots of info about that (including part numbers, cost, steps to install it yourself, etc.):
https://www.rolexforums.com/showthre...e+clasp+thread
As for a standard Speedmaster Pro bracelet, I'm guessing removal of 1 link from a full-length bracelet will result in a good fit on your 7.5" wrist. I was helping a friend size the bracelet on his new Speedmaster, and his wrist was probably 7.5". With one link out and the clasp set on its shorter micro-adjust hole (there are only two holes) it was a bit looser than he liked, so we took another link out and set the clasp on its longer micro-adjust hole, and this was undoubtedly too tight. He settled for one link out and a slightly looser fit than usual. I checked with him a couple of days later, and he was doing fine with it.