Harley.

If your going to go more agressive on the throttle then go with the 45A to be safe. The small diference in weight whon't hurt the performance of the plane. You can use the 11.1/2100's but don't over do it with the throttle or you will burn the motor or ESC. Now about how long of a flight, that depend on your way of flying. A 2100 can last as much as a 1500 if your agressive all the time, if not, it will last longer. If your planning on using the 2100, go ahead they whon't affect to much the performance.

Like RCmob said if you use the recomended propeller you should be fine. But for me 34A is to close to 35A so if it was my plane I'll go with 45A or try a few other props and check the amp drawn for each with a wattmeter and chose the best. A very important advice: make shure you have a good flow of air so your system don't overheat and shut down. Any other question feel free to ask.


Fernando