Osorio my friend you are using the wrong epoxy. System 3 T-88.
I do not use 5 minute epoxies from a hardware store as most of them are not strong enough.
So I was turned on to System 3 T-88 by a couple of the guys here and I have to tell you it is very very very hard. You will not press a fingernail into it. I think I have a video somewhere of me slamming a cup of it against the concrete and it bounces really high with a tight resonant crack. I have glued several test boards together with it and beat them against the concrete with results identical to titebond (breaking somewhere other than the joint). One other good thing is that T-88 does not go bad (titebond that has frozen or is old is not good for anything).
I am a proponent of titebond and I build 90% of a guitar with titebond. However titebond and really oily woods do not produce a bond on joints as strong as T-88.
I use titebond for my neck laminates, body glue ups, most tops and headplates.
I am planning on testing West Systems Epoxy more this summer (harder to use because it must be measured precisely).
Officially I use T-88 for most fretboards and some neck joints (if it is not super tight) and oily tops/headplates.
Use more clamps. I have posted several articles explaining how you should clamp joints to get proper coverage.
And of course
http://www.titebond.com/Download/pdf/HowStrongisYourGlue_FWW.pdf
Here are a few other articles to read
How to Glue-Up Joints: Different Woods Need Different Clamping Pressure - Fine Woodworking
How to Glue-Up Joints: The right number of clamps - Fine Woodworking
How to Glue-Up Joints: Tips on gluing - Fine Woodworking
Of course I knew you did not use an ordinary epoxy glue, I would be roockie to think so (LOL).
Only reported my little experience with epoxy (5 min) gluing little things, where there was not great resistance mechaninc required only to show that I had no experience with epoxy in fact.
I thought the cure of the epoxy was shorter than the vinylic, and produce a stronger joint, increasing productivity and quality at the same time, but you have reason to use epoxy only for oilier woods. Nice articles, it's always good to remember things and learn others!
About the switch problem, I also thought of a blend/balance control with a ordinary pot.