Kindle- all sails have an angle from the head
to the boom that has to be correct for the boat. If he is just shortening it by taking the bottom out, well he should do a lot of sewing. If he was taking the head
off, that will, as Eleven says, change the center of effort for the boat and may give it too much weather helm
. If the angle is wrong, he will have to cut alot off the side and top- and do alot of sewing.
Don't get me wrong- I love cheap
. But I would not give him a dime till I tested in in various wind
conditions on my boat. If he will agree to that, maybe you have a deal.