BCY has servings they reccomend for end serving, but I've had equally good results with Halo, 62XS, and nylon. If there are no rough or sharp spots, there should be little wear on the loop serving. On the other hand, you get a lot of servings from one spool so it's not a big investment per string.
Thick serving on a tiny string is apt to slip. Rod Jenkins experimented with padding the loops on an endless string, and he found that over time the padding is worked to the back of the loop and isn't doing anything. I think he used white for the string, red for the padding, and clear mono for the serving to see what happened.
I'm not "into" super skinny strings, but if I were I guess I'd just double serve the loops to build them up.
The best serving tool I've used to date is the Cajun--less than $15, and I'm still using some of the ones I started out with many years (and thousands of strings) ago. I have a different serving tool for each different spool of serving--near 50, I think. It's convenient to not have to swap them out every time you need to change serving colors, types, or sizes. I modify mine by adding a longer bolt and some fender washers for added weight.