about 3" above where my nock set would be to about 3" below where the string would hit my arm brace. I serve my string while it is strung on the bow and eyeball it.
I ordered a string once that the maker made both loops the same size, served the string long enough that it didn't matter which was top or bottom. the reason he did this was if the serving was getting frayed under the nock, the shooter could flip the string, reset the nock set and keep shooting without reserving.
I have more issues with the stands getting worn out in the Flemish loops than the serving getting worn. the loops get the rub more. this is where the endless loop strings shine, the loops are served and protected better.