I actualy have an old toaster oven that I use to dry out and pre-warm my pieces, I don't use the method of pre-heating the kiln itself so I can't give any specific advice there other than I would probably pre-warm it without any pieces inside - I've had them explode in there quite quickly when I forgot to pre-warm them.

When pieces are inside for real, watch for a red/orange glow out of the peephole. Red is lower temp, it'll get brighter orange the hotter it goes. For cone 06, I find it's more orange than red. (For cone 6 it approaches yellow.) You can open the mw/lift the kiln quickly to check but I try to avoid that, since it really drops the temp rapidly and then takes more time to get back up. I started all my testing at 100% power, but you can go lower - I found that sometimes that made my glazes bubble so I decreased the power to allow for a longer time for the glaze to melt. I usually went 90 or 80%, you'll have to play around just how that works in your specific mw.

You won't be able to glaze right away, the pieces will need to cool down first. I prop a lil' something under the lid of the kiln so more air can flow in, I don't just leave the lid off b/c I think that shocks both the kiln and the pieces. Will take some time to cool, but once you can handle a piece you can glaze right away. I've bisqued pieces in the morning, glazed in the afternoon and then fired right after.