Hello,
I learned to shoot right handed, while being right eye dominant. In HS, I was the state champion in three position shooting. My Junior year, I suffered a right eye injury. In a matter of months, I taught myself to shoot left handed, won the state championship again, and went on to compete at the national level in college.
I had absolutely ZERO challenges learning to shoot left handed in prone, even with the inclusion of an opaque blinder to correct for cross dominancy. In many ways, it makes sense for a right handed person to initiate the trigger with the left hand while supporting the weapon to the right.
I have since had a custom rifle built for FTR and elected to have it LBRPLE. If I had it to do again, I would highly consider a right handed action in a left-handed (or ambidextrous) stock. If designing for maximum speed between shots, the value of this configuration still warrants careful consideration. When building loads for my father's rifles, I often find it very handy to work from the right side as a left handed shooter. For FTR, I can see the merit in keeping the trigger hand and shoulder/grip pressure consistent by working the bolt on the right (counter intuitive) side. That being said, the added weight, improved tracking, and reduced shooter interaction of F-open might change that preference. Having experienced the ability to load from the right as a left handed shooter, I don't see myself ever ordering another left ported, left handed stock unless competing with a sling.
You should also talk to other shooters who make this decision based on the style of rest that they use.
I say, when ordering custom, get what you want. Go to a match and get some time behind both. Buy the finest with no plan to sell or trade down the line and you'll appreciate the quality every time you get to use it.
Luke
