I also have a US Spar furling main on my Beneteau 281. At first, I had trouble getting it deployed but I replaced the oversized outhaul and furling lines with the correct ones, had the main cleaned and rehabbed and now everything works very well. Many folks talk about releasing the vang, the main sheet,the topping lift and adjusting the halyard to help furl and unfurl. I haven't noticed that all that advice helped me any, as a matter of fact, I get better results with some vang tension, I think it puts the boom on my boat at a better (90 degree) angle to the mast. It also helps for me to have the wind to starboard because the sail gets a better entry angle into the mast. The other really important thing is to pay attention as the sail enters the mast (keep tension on the outhaul) so that you don't get any folds or creases. If you do, it will make it harder to deploy the next time. If I have furled the main in very windy conditions, I commonly unfurl and refurl the main after I get docked just to make sure that it is stored smoothly. It only takes me about 3 or 4 minutes and it is worth it. This still is easier than flaking the main and puting on the sail cover.If you can furl and unfurl it, what do you feel that you are missing? Are you having any specific problems?As far as sail trim, it is mostly on-the-job experience. I have found having the loose footed main gives me much more diversity with sail shape. For me, trial and error is the best way to learn sail trim but I am by no means an expert.Good luck