I have a Snake coil on my F75 and it performs well. Not sure what you mean when you say it "seems to lose depth"? If you already have a Snake for your G2, I wouldn't be afraid to use it, that's for sure.
For serious nugget hunting I would recommend the Tek 10" eliptical, or 5" round. I would think the Snake coil would perform well, or the NEL Sharp 5" round coil also. I am currently thinking about getting a NEL Sharp 5" round coil for my G2+.
Usually the ground where nuggets are found is hotter (more mineralized) than the normal dirt we detect for coins and such. The larger 11" biaxial coil will certainly work, but, a larger coil can be more effected performance wise by that mineralization, possibly causing a bit less sensitivity to the tiny nuggets. Most experienced nugget prospectors use the 10" eliptical as a general purpose nugget coil. It gives decent depth, plus good performance with both larger and tiny nuggets. The 5" round gives the best maneuverability in tight spots and excellent response to the very tiny stuff.
Additionally, the Tek 10" and 5" are closed designs which most prospectors prefer so they don't snag on brush. HH