Minimum height loss in the turn was achieved with maximum practical angle of bank.
Actually, not quite. Minimum height loss in a stable gliding turn is achieved with exactly a 45-degree bank. Any less than that and you're just wasting the horizontal component of lift, which you need to make the turn. Any more than that and the increased induced drag, combined with the higher stall speed will increase your RoD too much. The best balance is found at 45 degrees. Ghenghis the Engineer has either done the calculations himself, or has a reference for that. I verified this in practice.
Slightly less height loss can be gained by performing a semi-aerobatics wingover-like turn, but this is such a wild maneuver for so little gain that I would not even consider that in real life.