Man Muddy I'm trying to think back when I started to use Muzzy's. I guess it was more like 7 years ago now that I think about it and like you I was shooting 125's on a 2413 arrow. They dropped like a rock once I got out past 25 yards. I used what ever I could get my hands on before that. Thunders, Satellite, etc.
I think the 75 grain will do fine on deer. Rack has killed two elk with a 100 grain so a 75 grain should do fine on deer. The only thing I would be careful of is getting the balance point to far back on the arrow. If you do, it can make your arrow fly kinda crazy.