I have a 335, it will have a Riff Raff bridge and Stormy Monday neck when I have chance to change the pickups. It is not straightforward! you need to take cotton or fishing line or if you have a tool to really tighten them, plastic ties. Wheatever you use needs to be about 18" (450mm) long. You tke off the knobs from each control and the switch, and then fasten the cotton or whatever around the stem of the control and then drop them inside the guitar. It is a good idea to tie then all the strings together on the end avay from the controls, this way they can't go through the hole too (voice of experience!). You then unsolder the pickup from the volume controls and fix like any other.
You pull the controls back and jiggle them to fit through the hole, fasten the nuts, and finally stop sweating and swearing!!
Sound wise, they sustain more than a solid guitar and have a great clean sound as well as an excellent rock sound. They can feedback more easily too though.
You shouldn't put a high power pickup onto them. You willl loose the 335 sound. Any of the PAF types should be good, though I'm not sure of the Black Dog, as the 335 has a mice midrange anyway.
