I purchased 4 sails from Lee Sails in about  or . I had recently become the inhabitant of a 10 tonne Dansk Jagt replica built in 1974 (nee circa 1810).
My experience was that Lee Sails tried to also sell me sail covers, although I said nothing about sail covers in the request for a quote. (I was also able to ask the wife of the previous owner of the vessel about this - as the previous sails were from Lee Sails. I was aware there were no sail covers when I bought the vessel. But Lee Sails claimed to have made a full set of sail covers for the previous owner. The mystery was explained when the wife told me the husband gave the sail covers to a charity recycling store as none of the sail covers fitted the sails.)
My further experience was that there was a 10% low season discount for buying
at that time of the year (which could have been about May or June ?).
Another plus was that they were very patient in clarifying with me by e-mail exactly what I wanted.
On the down side, they wanted payment in full in advance.
Further, both up and down, you can pay by credit card, but in that case they make a surcharge (currently 3% extra).
Further down, it took about a month more to make the sails than Lee Sails estimated it would take.
So the whole thing took about 3 months or so from start to finish. I suggest you do not leave your sail replacement to the last minute, think ahead.
Once the sails were complete, I made a request that they photograph them and send me digital images
of the sails before shipping
the sails out. But they refused to do this. I thought it was a reasonable request. As it turns out one sail departed from one I specified in one (fairly trivial, but noticeable) respect. Not that they got the size wrong, instead one eyelet was missing.
I think I have Rolly Tasker sails for an Australian Rainbow class 12 foot scow, but they were made in either 1972 or 1973. (Still okay I guess, they have not had much use in all that time, they now sit in bags at home.)