Well, for starters, a solid-body guitar is unlikely to "breathe" in the way that one presumably expects of an acoustic instrument. The body is supposed to be an inert chunk of wood, and is not responsible for the sound of guitar in any but an attenuated way. Your electric guitar's sound comes from the strings disturbing the magnetic field of the pickup, as opposed to an acoustic instrument, whose sound is generated by the string inducing sympathetic vibration in the body wood, especially the top. As such, the thickness of your finish is really unlikely to have a discernible effect.
That having been said, it sounds like you have a preference for a very light, low-luster finish, and you should definitely pursue what you want, rather than listen to some internet yob prattling on about whether wood breathes.
The Warwick product appears to be predominantly beeswax in an oil emulsion, which is likely not to be a particularly durable finish, but very easy to repair. If that's okay with you, your work is done. But there are also poly finishes you might consider. Wipe-on or gel poly coatings can be extremely thin, and are very easy to apply. THey are not the thick, hard-as-nails finishes you get out of Warmoth or Fender's non-custom-shop axes - you lay them on very, very thin, and they build very slowly. This allows you a great deal of control, and ensures you won't over-apply the finish. The are available in a variety of sheens from matte to gloss, but the gloss won't really ever get up to a factory-applied and machine-buffed look unless you kill yourself to get there (i.e., expend tons of elbow grease, or get your hands on a decent quality buffer yourself). Folks around here have had good luck with Minwax satin poly for both necks and bodies. The Minwax product also has the advantage of being available at your local hardware store, unlike lacquers and other specialty wood finishes.
