I was reading a post here on this site where a 2900kv was used but on 3S. Page 2 by Grimguard. Figure that 2900 x 11.1 x.90% = 28711rpm on your 436 metal prop. Lipo weight 2S for the 2858 motor should equal 2900 motor on 3S so self-righting works correctly, hope you follow me. Read the page 2 first before jumping. 4400 try a one size up in prop size first for heat of motor and esc first, ok=ok=ok!