When wrapping guides, I know that consistent tension is the most important thing, but is tighter always better as far as wraps go?, Does is make it hard for the epoxy to soak into the thread if you wrap too tight?

I think "tighter" may not be a good choice of words for wrapping. Snug might be a better description. If you can't move the guide with moderate pressure after wrapping, the wrap is too tight.

You want the thread wraps to be just tight enough to still allow movement of the guide. Too tight and you can stress the blank. If your tenstioning devise tensions the thread itself this is not good as it can cause fraying and if you back off the tension this may make the wraps to loose in avoidance of fraying. Nylon thread is very stretchy. Stretch is greatly reduced after the application of thread epoxy. Furthermore, when wraping a guide/blank you should pack the threads together regularly and burnish well after wrapping. The use of CP will inhibit the saturation of threads more than tension, packing and burnishing will, but the use of CP makes moving or replacing a guide much easier. The thread epoxy will saturate well on correctly tensioned, packed and burnished threads.

Chris and Bruce gave you the correct advice. If the guide moves with no restrain it is too loose. If you can’t move the guide without using a lot of pressure, it is too tight. The guide should move slightly when a little pressure is applied. Packing and burnishing is important. Doing this well also show if the wrap is too loose;
Good Wraps Bob

Enough tension to stretch the Thread, but not to its elastic limit, is another bench-top criteria for setting a useful tension. Different brands & types of Thread material will take different amounts of tension to put you in that "stretched but not too stretched" range of tension on your set-up. ...

Better Guide Foot preparation will also make better use of a lower Thread tension. And as most R-B'ers would say, it is usually easier to work Thread with a lower Thread Tension on it than one with higher tension on it.
-Cliff Hall, FL-USA.