With tails you don't use the oven. Your best friend is a Dremel rotary tool to cut the lights open. After painting the housing and assembling everything you have to glue pieces together. I used JB Weld, worked great!
For headlights - 230-240 degrees for 15 minutes. Trust me, that's the best option, atleast for 02-07 WRX and STI headlights.