Wire from a wire feed welder works well, too. I found it is easier with the headliner out. You can fish the stiff wire throught the A pillar from the space between the inner and outer roof sheetmetal with the headliner out easier. Onece you get the wire that far, getting ot the dome light is relatively easy. Used the same technique to get the wiring to the radio speakers, which mount in the OE location above the mirror.
