Re: insulfrog or electrofrog ?
You can always use Electrofrogs. Insulfrogs may not work well with short wheelbase locomotives or those that only have a few wheels of pick-up on each side. Insulfrogs are a little simplier to wire up. So if you want to use Insulfrogs, I'd buy one of the highest size number you intend to use and try it out with all your favorite locomotives. You still might have a problem with a locomotive you buy in the future.
You can also use Electrofrogs and not wire the frog unless you find you need to. Note: The size the dead area on an unpowered Electrofrog is a little larger than that of the Insulfrog. If you do this, be sure to drop the frog wire down through the benchwork in case you need it in the future.
I use the Electrofrogs so I never have to worry about dead frogs. You can learn more about Electrofrogs and Insufrogs on my website at:
Wiring For DCC