I see no numbers in the "female" IDPA rules. All it says is
"Holsters for females are exempt from F criteria but may not cant the holster away from the body past 90 deg to the ground." Rule F is the part about belt tunnel gaps and thickness of back pieces over the belt. It seems to me that she can have whatever spacer is required to make the holster hang vertical.
"Female shooters are exempt from this test." (3/4" gap between body and gun.)
"Female shooters are exempt from this criterion." (Several items, including no drop loops, no drop in the holster itself, offset back, and no daylight gap.)
Not more generous requirements, EXEMPT. She can have whatever holster she needs to get normal positioning of the gun.
Unfortunately, I do not know a brand name to recommend.
I have a few facts and a lot of opinions.