I don't really necessarily see a reason to avoid electrical tape--it's functional and can easily and cheaply be replaced when necessary, but I understand that folks don't like the way it looks--not necessarily even aesthetically, but the just the concept of having electrical tape on your gun, and I guess you could get some adhesive "glue."
That being said, I've been working with a lot of different types of remote switches recently, and have had to swap things out fairly often--IMHO:
Adhesive backed Velcro for the pad has, for me been effective in retaining just the switch when used on a flat side (not so much directly on rails), you just need to make sure you clean the surface with an alcohol swab before application and stick it once, if you mess up the placement, remove it and use a new piece, don't try to "re-stick" the same piece of Velcro. Once you've placed the adhesive pad in the desired position, leave it alone for a while to let it set. Most of the time when people have problems with adhesive Velcro sticking, it's because of one or all of these things.
Once you've done that, the pad itself should stick fine, and can easily be "reinforced" by small zip ties (you can use the zip ties to attach the pad without the Velcro, but the combination allows for a pretty solid mounting).
For wire management, I like LaRue Index Clips for routing applications, while for simple management I like to use Velcro cinch straps and/or McNett Camo-Form, both of which are fairly secure, low profile, re-useable and replaceable, and look fairly professional when done with adequate care (McNett can be cut to width/shape).
~Augee