Riddle -
My experience, going from a 50 to a 45: it's hard to do stuff like a regular crucifix, a pole sit, and a CAR at first, but all my other stuff like the inverted crucifix, knee pit based moves, and the plank have been fine. I remember attempting the gemini knee position on my 50, and it was really awkward for me (my thigs are pretty large.) Now that I have my 45, it's no problem, so I think that move is actually easier on the smaller pole. Learning new tricks has been fine too cuz you have no basis for comparison; you just squeeze way more than you used too, that's all, which is good cuz you build more muscle! 😀 I think a 40 or a 45 is a good idea for you. You can start with one, and get another later when you get moola (as we all do...darn the pole addiction! It's such an expensive one!)