If you are planning on a different riser anyway, why not break out a wood rasp and modify your current riser? Even though you may not be a woodworker, unless you rasp it in half, what have you to lose? I have modified several bows to better fit me. Go slow with the rasp, check the fit/feel often. Once you get pretty close to what you want, switch to sand paper instead of the rasp. Use coarse 50 to 80 grit and work your way down to 250 to 400. Finish with TruOil gun stock finish. You just wipe on really thin coats, let dry and repeat. I like to buff the last coat with 4-0 steel wool to break the shine and give a bit of a satin finish.
Unless you plan to try to sell it, I see no reason not to give it a try. It might just turn out to be a perfect fit. If not, you can still have a riser built by either of the members who offered. If it works, you have an economical solution. If not, you aren't out much money.