Darrell, Hi,
If you are concerned only with Commissioned ranks then Page 5588 (20 Sep 40) of the London Gazette might be a good place to start. Also, if you search the LG for Officers numbers in the 80016-80496, and 160016-160026, ranges you will find quite a lot of ’em were S Rhodesian. Could lead you to Pilots and Aircrew!
If you are also investigating non-Commissioned ranks then send me a PM, or email, and I can give you all the details of Rhodesian Enlistments from Wg Cdr Jim Routledge’s lists in The Orders and Medals Research Society publication of 1992. You can simply work out the numbers from the batches (but remember not all of ’em may have been issued).
HTH
Resmoroh