Have a gp3500 modded what is the best coil for maximum depth?

I have a 11 inch NF advantage
and a 18inch current series Goldstalker coil.
But being a bit greedy i want a coil for maximum depth and penetration in wa conditions for larger possible targets at depth. Will the tw coils i have suffice or one more larger one added to the kit??
Appreciate any sensable input.

G'day explorer, You will get some serious depth with the 18" and will be surprised how deep the 11" will go too, of course it will depend on many factors as to how deep it will actually go. Personally I think that the 18" would be sufficient but there are alot of guys swinging much larger and then there are some that will not use bigger than the 11" also.

Have a read of the coil section on the main page, you will find some good info in there.

Cheers

G'day Explorer.

As GoldstalkerGPX stated,Maximum depth and penetration,on all types of nuggets,truly depends on actual ground conditions.
The two coils you've mentioned will more than cover a wide range of both small and large nuggets at various depths,in mild to medium mineralized ground conditions.
The only other coil i can personally recommend for your modded GP3500,which can be used on just about any type of ground conditions, which does offer superb depth on large as well as medium sized nuggets,is the Commander 18 inch DD.

Cheers kon61.