I used thunderstruck list that he made to help figure the bulbs out and came out good for me. The T1.5-x bulbs I upgraded to high power but the rest I used. Pictures in my build thread.
http://www.truckmodcentral.com/forums/f63/change-color-your-95-gmt400-dash-lights-977/index3.html
Instrument Cluster Illumination
Six 194 bulbs and T3-1/4 sockets
Replace with WLED-x bulbs and new T3-1/4 sockets if needed
HVAC Controller Illumination
Four 74 bulbs and T1-1/2 sockets
Replace with T1.5-x bulbs
A/C and Recirculation Buttons
Two 74 bulbs and T1-1/2 sockets
Replace with T1.5-x bulbs
Dome Light
One 42mm x 10mm Festoon bulb
Replace with a 4210-xHP (Festoon) bulb
Dome Reading Lights (NOT the overhead console lights)
Two 44mm x 10mm Rigid Loop bulbs
Replace with RL4410-xHP9 (Rigid Loop) bulbs
Courtesy Floor Lights
Two 194 bulbs
Replace with WLED-x6 bulbs
Door Lights
Two 194 bulbs
Replace with WLED-x5 bulbs (some minor trimming required)
Glovebox Light
One 194 bulb
Replace with a WLED-x5 bulb (removing the metal bulb shield will help output)
Ashtray Light
One 194 bulb
Replace with a WLED-x6 bulb
Headlight Switch
One 4mm Neo-Wedge bulb
Replace with a NEO4-xHP bulb
Driver Side Power Windows & Locks Switch
One 4mm Neo-Wedge bulb and one 3mm Neo-Wedge bulb
Replace with a NEO4-xHP bulb and a NEO3-xHP bulb
(IMPORTANT! You must use the High Power 3mm bulb, the ordinary 3mm bulb is too tall to fit)
Passenger Side Power Windows & Locks Switch
One 4mm Neo-Wedge bulb
Replace with a NEO4-xHP bulb