What style table did you build? What type of vacuum system are you using?
On the plastic, try going hotter. I use ABS so my experience is different, but it seems like a lot of this process is determined through experimenting with the exact setup and specific plastic. The ABS doesn't reflect a temperature to go by with a non-contact laser thermometer so it's more important to go by sag and results. The same is probably true for what you're doing. With my setup (oven on top) I left plastic at the oven until it started to degrade & melt just to see what that looked like. Helped me understand what the limit was for sag and temperature.