Here are some stitches from the saddle I am currently sewing (my first). If these threads were all Kevlar I calculated it should break at 17,550 lbs. If all polyester half of that or around 8,500 lbs. These are about half polyester and half Kevlar so it should break around 12,000 lbs. I know we don't always have a 4 inch wide strap to sew, sometimes only 1 inch so the Kevlar can get more strength from fewer stitches. I think I already admitted I don't need Kevlar but why not go with the best. Many people do.
The second photo shows the backside of my strengthening stitches. I used a different machine than before and had difficulty getting the top tension high enough. I was maxed out on top tension so I lowered bobbin tension and the last line came out OK. I thought about ripping out the looped stitches but as you reminded me, I have more than enough strength even without them unless I put on a lot of weight.