What is Your draw length first? Is it 27"?
And how long are the arrows?
I would start out with full length arrows, 40# to 45# spine like you have, 30 inches long! Or even 35# to 40# spine. The farther a bow is out from center shot, the lower dynamic spine arrows you will need. And 1.5" is a wide handle! Nothing wrong with that though, just the bow style. All my bows are 3/4" wide at the handle, even up to 60# draw weight. Never had a handle break.
When tuning arrows. You want the arrows to be a little weak at first, so you can cut off say 1/4" at a time and shoot them again to tune them in. For every 1 inch over 28", the arrow decreases 5# in dynamic spine weight, and for every 1" less than 28" it increases 5# in dynamic spine weight.
Another thing you could do is raise or lower the brace height. But only change one thing at a time and see how it affects the arrow flight. But I'm betting you need weaker arrows.
Click on knowledge base then bow tuning..
http://www.acsbows.com/index.html