okay so ive been lurking here for like 6 months and finally pulling the trigger on my first actual build instead of just buying a prebuilt. going with a 5 inch freestyle setup, probably the iFlight Nazgul frame or something similar, havent fully decided yet.

my question is about matching motors to the ESC. i understand the basics but im getting confused reading different threads because some people say the ESC amp rating needs to headroom above the motor's peak draw and others are just like 'slap a 45A on anything and call it a day.' im looking at the BrotherHobby Returner R5 2306 1700kv motors and was going to pair with a 45A 4in1 but honestly dont know if thats overkill or if i should go 35A to save a bit of weight.

also slightly unrelated but should i be worried about the stack height on a 30x30 vs 20x20 for a 5 inch build? feels like 30x30 would be more solid but maybe im overthinking it

45A is fine for those motors, honestly on a 5 inch freestyle quad youre rarely hitting true peak draw on all four simultaneously and even if you do its a spike not sustained. the 35A would probably be okay too but the weight difference is like a few grams and the peace of mind isnt worth it imo. i ran a 35A 4in1 under 2306 2450kv motors for almost a year before i smoked one and that was definitely my fault not the ESC's.

on the stack size thing ? go 30x30 if your frame supports it. mounting is more secure, easier to work on, and honestly most decent 5 inch frames are designed around 30x30 anyway. 20x20 is more of a 3 inch or micro thing these days.

what flight controller are you thinking? that matters almost as much as the ESC choice honestly, some FC and ESC combos from the same brand just work better together and save you headaches with BLHeli config and telemetry. i went with a Speedybee stack on my last build and setup was way smoother than mixing brands