On the Morgan I do the same as Dave DW. Onoccaisions I use dometic stainless steel hob clener for a "deep clean around spoke nuts etc."
I use one of these on my two Mercs both with Black gloss diamond cut wheels.
https://www.eurocarparts.com/p/trad...XuN_N-gIVyJ7tCh31HQt_EAQYByABEgLIMfD_BwEThey can be bought Amazon, Ebay etc. The Micro fibre sleeve is easily removable/washable.
Use bucket of water and this tool. Once soaked, the micro fibre tool cleans off all the inner rim dust etc (even behind calipers). Once cleaned its important the wheel inner is spray washed to take away dirty water etc..
Clearly the "big" difference " is how often you do it. If you do it often enough just a dry wipe over with this brush cleans the inner rims to a shine with no need to spray.
I am a "clean shoes, clean wheels anaorak". Even when I clean the car I do wheels first.
I dont use any chemicals other than the S/S cleaner for the Morgan