Just stick to square. I wouldn’t say circle is exceptionally helpful for 360 chars, since sometimes you want to end up at a diagonal upward position to complete the motion rather than doing a full 360 (for example), and this is easier on a square. Plus most 360 chars have other motions. DPs easier on a square. DB charging easier on a square. Charge-char supers easier on a square. No char really gets an advantage from using an octagonal gate, and circle is debatable.
I recently modded a square JLF gate to have little triangular cuts on the cardinal directions, to give a tactile feedback on up/down/left/right if I’m on the gate. I honestly don’t think I’ve ever noticed it during play, but I like to pretend it is helping.