Mike,

I don’t have a definitive answer to that question, but my very heavy (12 lbs. I think) Losmandy side-by-side saddle seems quite solid and rigid for the small but heavy refractors I put on it.

I’m sure others will correct me if I’m wrong, but I suspect that the lower scope position (closer to the mount’s pivot points) of a side-by-side setup potentially make tracking and guiding slightly more accurate.   But that’s a wild guess.

Woody