I understand what you're saying.
Honesty though, since I fly here at altitude(5300'), I can relay this...
I had an 89" Spitfire flying on a turnigy 50cc Gasser. It flew exceptionally well on a 20x10 prop. That turnigy 50cc is not nearly as powerful as a DLE or DA of same displacement.
The spitfire weighed 27.5 pounds.
I can't imagine an fg60 is going to have a problem here. If it can swing a 22x10 @ 6500 .....thats the same rpms I was seeing the turnigy motor swinging a smaller 20x10 on a similar size and weight plane.
Will it perform here the same as at sea level? No... there will be a difference yes, but not that great of one.
An fg90 would sure be a great motor for the 190 here for sure, but the fg60 will perform quite well also.
Personal choice of the builder... Having options is a great thing.