When motoring to the ends of the arc (15W and east, west of 103W), my dish is like an old man sitting down. It's easy to get down, but it's a struggle to get back up. So when my dish is moving back toward the higher elevations from the ends of the arc, I may need to electronically bump the dish a bit back and forth to get it to move properly. Maybe some commands are getting lost. I've developed a technique.
I believe that is to be expected. I realize the newer 2100 models have been beefed up. However, that model has many clones out there. I see some ads now claiming 1.2 metre and 33 lbs. I think that is total hype. A couple years ago, they were only good for about 25 pounds.
My starchoice 1 metre weighs 33 pounds. If I had a good LOS for a motor, I'd put a Staab HH120 on it, or possibly the new SG 6100.
Your dealer in Halifax quotes:
The SG-2100 is the finest quality DiSEqC dish motor you can get.
Designed by Moteck Electric Corp. of Taiwan, this rotor can be used to motorize a satellite dish sized up to 1.2 metres. Any offset dish with a U-bolt or pole mounting, 120 cm. aluminum or 95 cm steel. Winegard 30", FortecStar dishes.
Fine print for 1.2 metre says aluminum.
Wish you the best of luck, but think you will have trouble at the arc ends as you have stated!
Catamount