I'm new to archery, so I'm certainly no expert on this subject, but for what it's worth, here's what I've got...
My draw is somewhere between 26.5 and 27". My bow is 48@28, so I'm right around the same draw weight as you. I just recently bought a Toelke Whip and Dan, who I have been told knows his stuff, told me to go with CX Heritage 90s cut to 28" and 140grain points. I'm still working on my form, so I haven't bothered doing any tuning/testing, but I did recently take a 2 day class with Rod Jenkins and he agreed that my setup was in the ballpark.
I don't know if I'm right about this, but it seems like it would be easier to weaken the 90s, if that was necessary, rather than stiffen the 75s.