Ballpark would be 60-65 or 65-70's. Here's why.
Actual draw weight - 45# - 45# spine
29" draw - add 5# spine for every inch past 28"=50# spine
shelf cut past center - add at least 5# spine=55# spine
"Fast Flight" type string - typically add 5# spine=60# spine
135 grain point - add 5# spine for every 10 grains or so over 125 (subtract for lighter points)= 65# spine
If you go with a hardwood shaft that is extra heavy (ash, maple, hickory, etc.) you may need to go another 5-10# heavier in spine.
That's just a ball-park calculator. There's lots more variables--how the string was made, your release, bow performance, etc.
It seems the better your form and release are, the wider the spine range you can get away with, and the lower you can go with spine.
Like most things, it will take some tinkering on your part to figure out what works best for your set-up.
Chad