As a USA recreational golfer who's played, probably, 35 courses in Scotland and Ireland, I have these observations:
(1) If, for whatever reason, the length of the hole is important when you play it, then by all means do your due diligence. If the holes on the course from the tees you are permitted to play are not long enough for you, then don't play that course. There are plenty of other courses with holes of varying lengths that could satisfy you.
(2) In my experience, the difference in yardage between visitor tees and member tees is inconsequential. As for the championship or medal tees, that's another matter. Personal story. One of our group visiting Royal County Down was a 1 handicapper and a very experienced amateur tournament golfer. He asked to, and was permitted to, play from RCD's Championship tees. Several days earlier he had played Royal Portrush from member tees (or the like) and finished one over. At RCD, from the Championship tees he shot something in the low 90s . . . so, lesson learned.
(3) A reverse experience. The only time I've ever played Carnoustie we were told that on that day we must play from the back tees - not the "way back" championship tees used for the Open - but the regular backs. Wow! It was a very long course.