@Hairic I finally went back and looked at your link. The chaps there are only $70. If I donated my time and used bargain leather, I might get them made for that amount. If those are the ones he wants, I think he should order them. I'm not trying to be negative. I have made myself, family and friends stuff that cost me more than you could buy it for. I at least tell myself that it is better quality and it usually is. Those are "patchwork" chaps. Zoom in on the picture. You'll see that each leg is made up of several panels of leather so the manufacturer can use all the hide. Making one pair at a time, that would make it more time consuming for me and lower the quality. You might have him look at these: https://www.foxcreekleather.com/1-6mm-1-8mm-motorcycle-chaps/ A little more realistic price and hopefully closer something you might make. Where you can shine is the custom fitting. Measure around the thigh at the crotch, around the knee(bent at 90 degrees), make sure the calf is large enough to go over pants and boots. I usually add about an inch to each of those measurements for my pattern. Another problem with off the shelf is that the inseam usually lands about halfway between the crotch and knee. You need to determine where they will wear them. On westerns, the chap belt usually sits just below the jeans belt. I've seen guys wearing M/C chaps from practically their armpits to almost their crotch! When they decide where they will wear them, measure inseam and outseam. I apologize for the rant/book!
JM2C