I have set up arrows for low lbs for kids, gals and the wife many times. 400-500 spine with a 125 grain point, can load the front a little more if you have a light arrow, I like to be around 400 grains. Cut them long for weight and spine as well as keeping sharp broadheads way out front.
Many critters killed from 35-40lbs, including bear and elk, a 2 blade broadhead razor sharp is key, magnus stingers fit the bill. Hunting with a kid and watched him arrow 3 whitetail with 35lbs, a little 3 blade on his set up actually, all shots were 20 and in and all buried to the nock, his draw was short maybe 24?
The wife and her friend both had a longer draw for ladies anyway, 26.5, both shooting right at 40lbs, her friend killed a 350 bear with a 4 blade muzzy and a 425 grain 400 spine arrow, complete passthrough.