I did this on both my '63 and '71 Avanti II. The best way is to first remove the front driver seat. There are only 4 bolts that connect it. Then you can lie on your back (with your head next to the pedals) and have full access to the underside of the dash. I would recommend throwing a few pillows / towels on both sides of the ridge on the floor that connects the front part of the seat. The pillows will distribute your weight around the ridge. (Your back will thank you!) It is best to disconnect the battery before doing work under the dash. When you replace a bulb, you can reconnect to test it and check. It will take about an evening to do if you do it leisurely. I found that the Avanti II was more of a challenge to replace the bulbs since there were a lot more wires and obstructions under the dash. The Studies had less clutter and were more accessible. Have fun. You will like the results!