Don't thin. Just use heat to make it more fluid. A heat gun is my preference, but an alcohol lamp works too. Let it soak in for a few minutes, and then wipe off the excess for drying.

If you thin, you risk inconsistent penetration of the silk threads once the solvent has evaporated out.

Here's an excellent discussion, including votes for thinning the epoxy. See the link to Chris Carlin's method in thread:
http://classicflyrodforum.com/forum/viewtopic.php?t=104486

I have used 99% isopropyl alcohol to thin epoxy.It works but as stated it does slow down the drying rate.

I use Threadmaster and mix the resin and hardener first. Then I mix in denatured alcohol. 1/3 resin, 1/3 hardener and 1/3 denatured alcohol.

I use a very small Taklon brush to gently work the epoxy into the threads around the base of the guide foot. Start at tip of guidefoot and work your way up. I then apply epoxy to rest of threads. My last rod, I had no air bubbles. Essentially, you are pushing air bubbles down along the guide foot and out of the threads.

There are some videos on YouTube having to do with Epic rod builds with translucent wraps.

Yup, same as Panfish.