Hiya! The subject of poles is close to my heart as I currently own two and am thinking of getting a third (I can hear my boyfriend now "What do you need three for??")
In short, I have a 45 TG and a 50 Chrome. I principally learnt on 45 stainless, so the TG was okay, but I did find the 50 a struggle when I first got it. I don’t regret it though, because i think practicing on a different size pole really increases your versatility and helps if your thrown in a unexpected performance or go in a competition where they have set sizes different to what you’re used to. If you already have a 50, I doubt you’d have much trouble going down to 45. I’ve been learning on a 38 brass recently (see, I’ve tried them all!) and it does make split grips easier. The only problem is with laybacks and superman style moves, you have to grip a lot harder until you adjust to the difference in width.
Anyway, that is my two cents, hope it helps with your decision! Either way, I’m sure you’ll have fun with your two poles!