Frank,
Life is full of compromises.
I shoot a lighter bow now too. Its 40#@29". I draw it back 31 1/2" so its probably between 45# and 50#. And I shoot ICS 300 Beaman Hunter with 300 grain heads. They straighten out fast and hit hard. Lighter spine arrows don't straighten as soon after they leave the bow, and if they are flopping around when they hit they won't transfer energy or penetrate as they should.
So my compromise is to get what shoots straight,with a heavy head for penetration,and a stronger shaft for durability and a longer useful life. The ICS 300 Beaman works best for me. Vantage Point makes a nickle-plated 300grain fieldpoint that hits the target with a satisfying thump, and they have a 300grain three-blade that is machined from a solid piece of steel. And thats what I shoot.
Good luck hunting!