Hi Jeff, and a warm welcome to the forum. grin
It's always great to have another Scott Bonnar owner onboard.

Re your question, I can't answer that....with my Model 45 I just set it to the height that I wanted for my lawn ( I have kikuyu) and locked it up at that and have never changed it.....It all depends on the front roller which travels in an arc...you can lower it to the extent that the bedknife blade will almost touch the ground, which is not good, to the other extreme where it is at an incorrect angle for cutting.
It all depends on your personal preference I guess. wink
Once again Jeff, :welcome:
cheers2

Please do not PM me asking for support. Please post your questions in the appropriate forums, as the replies it may receive may help all members, not just the individual member.
Kindest Regards, Darryl grin