I've installed a couple of glow gauges with no issues. It's pretty damn easy. I might do a "how to" writeup soon.
Not sure what brand of gauges you got... but I would recommend the indiglo's or reverse glows from UPR.
Their kits come with an adjustable bright intensity knob so you can manually lower or magnify the brightness of the gauges.
I bought my last set from UPR at Fun Ford Weekend at Ennis 2007 for $45 bucks. Installed them on my old 99 2valve. I lower the
brightness during the day (hoping it will lengthen the life span on the gauge LOL)
I want to say Americanmuscle also sales the exact same type of gauges but cheaper (and free shipping)
here's a shot of my indiglo gauges. Personally never liked the reverse glow style.

Reverse Glow Gauges
Call around and get some install quotes at local shops.
i can do it way cheaper - let me know
i stay in north texas (Rowlett,TX)