Hi Gav. I was in much the same position as you last year. I am purely visual and wondered if the outlay for a double stack for the LS 50 could be justified. I read in some reports that it dimmed the image too much and rendered the views of proms less detailed, while others said it was a great improvement. I finally bit the bullet and ordered a DS unit from FLO. It has turned out to be one of the best decisions I have made. The difference in the surface detail is night and day. Yes it did dim the image but not to any great detriment. As for the proms, it certainly does not make them any worse and on certain occasions I think it improves them. I also find that it enlarges the sweet spot and greatly improves low mag, whole disk views. Definitely one of my best decisions.