Our Roamer is a 41 Regal so the spots are a little different I bet.
What I try to do is position the strap forward in line with the bow side of the head bulkhead.
The stern sling is positioned about 24" aft of the salon sliding doors. This on my boat is just aft of the centerline of the fuel tanks. I am forced into these spots due to trying to balance the boat on our trailer and still fit the straps into openings on the bunks that carry a small part of the load. I have moved the slings back and forth at least a couple of feet from where they are placed today with no issues. If it was a Commander I would be a little more cautious due to hull flexing, which we saw with our 38 when being lifted. I think that Jim Wick at LPX
www.chrisparts.com can help you with some advice on your model.