Whoever ordered it should have discussed it with you first. Whether it's right or not...hard call.

AMO says the string should be 3" shorter than the AMO bow length (longbow or recurve)....BUT a lot of bows don't meet AMO specs. Actually it says the bow should be marked 3" longer than the "string master" that puts it at proper brace (the string master is a steel cable).

Any of the "Fast Flight" type materials will stretch a lot less than dacron, but if it's done properly either one is measured under 100# of tension--which should allow for the extra stretch of the dacron. I think even fewer string makers measure them properly.

String it up, check the brace, and go from there. You can generally shoot a little lower brace with a FF type material, but not normally a full inch lower.

Chad