I haven’t snelled a hook in years but I want to on some string leech patterns.
Doing a google it seems there are two ways to do it.
One …the easier one …has the line end going over the wraps…and the other doing loops over the bend of the hook has the line end coming under the loops…
Which is the best way?
do both of them and see which one works BEST FOR YOU! 
Usually the line is brought through the eye and looped around the trailer hook, without a true snell. Just wrap in a loop on the front hook, which is usually cut off at the bend. I have never seen one tied with a single piece of line and snelled to the rear hook but these are seldom tied for small fish and strength is a serious concern.
art
This caught my eye , hap…and I thought I might try it…l’ve tied them the way you mention…but the more string like leeches may have more motion…
The snell knot is tough sometimes, I have one of the Rudy’s snell tyers and it works good. The other option you can use is try a Uni knot for the snell it works pretty close, tie the knot on the hook then run the long end through the eye it makes it easier.
Fatman
The only way I have ever done it is with the loops going over the the line and hook shank around the hook bend. I think the other way is like a uni-knot connection.