What I did on padding the loop end on an endless D97 12 strand,I added 4 extra strands of D97 before I served up the loop ends.I wanted to use the same material as the string for an endless.But I guess you could double serve it too.I not sure which would be better,that was my only padded loop endless,I haven't done it on dacron yet.I bought a endless padded loop 8125 for a DAS I had a year ago,then I started to make my own.I'm not sure how that custom string maker did that one.The D97 endless I made is still holding up.This is how I did the D97,I haven't made that many endless loop strings,wish I could have been more help.I used the 3D serving on D97 and use nylon serving for my endless dacron.