Michael, I think you are looking to far into it.
The dimensions you have shows me that under compression they would be better but how long will they last is uncertain. You say you have Brophy's book. How is anyone going to know what the compression size is at the tip, you don't.
The mainspring that I am looking at the dimension opened is .930-932.




Put it in and try it. If you have never taken a side plate mainspring off, you are in for a surprise. Wear glasses.