Anastrozole (Arimidex) should only be used if you have labs to indicate that it needs to be used. Anecdotally, transdermals seem to have less aromatization issues than injections (that's one of the very few advantages they have.) Individual physiology is a big part of the picture, too. If you don't need it, don't take it.
Why do you think you'll "feel better" with injections? If someone says they switched to injections and felt better, that's probably because the creams weren't working for them or their dose wasn't high enough. Conversely, some guys use creams for years and it works great for them. What were your last labs while using the T cream? You do need to have that monitored because the efficacy can change over time in the same individual, your system can absorb it less. But I agree with VT that if your protocol is working, why change? Creams were never a practical option for me because my job is in the water and I work out daily and sweat heavily in general...but if they worked for me, I'd be willing to give them a try. Then again, I don't mind my shots anymore.
No, your height doesn't have any bearing on what dose you need. The only way to know what you need is to test, dose, re-test and monitor periodically. Everyone responds differently. 100mg/wk is just the starting dose, you may need more or even less.