I agree with Don. I prefer to keep all turns at least 60 degrees. 45 should be the absolute minimum and should only be used as a last resort. The bigger the turn area the greater the angle should be. The scariest I have ever flown was a big ring at Uvalde with a cloudstreet that bisected the turn area. Everyone lined up on the street and flew it in and out. Nothing like 45 gliders at cloudbase at 110 knots flying out and back on one street. This was pre-Flarm and I was afraid to pull up because of the loss of forward visibility. The midair at Uvalde was event that really made most tasking committees realize that nearly 180 degree (0 degree) turns must be avoided.