hungNtree ..............
The whipped loop and attaching heavy mono via a nail knot with a Perfection Loop tied into the mono are both acceptable for smaller fish such as trout and small Bonefish. BUT if you are going for larger quarry, such as Tarpon and the likes these conections have been known to fail.
The safest and easiest method of forming a loop in a fly line is to form the loop by doubling the fly line back on itself and tying two eight turns nail knots on the doubled line close together. I like to use 40 # PowerPro. The gelspun really bites into the line. Then coat the knots with a flexible cement. (Pliobond is my preferred cement.) The resulting connection will be almost stronger than the original line and will hold up to any size fish.
Hope this helps,
DickM.