I have a dehydrator that I have made jerky with many times. The top has a grate or you can turn it and it has big holes.

I need to leave the jerky in over night. I have 7 layers (trays)

I'm thinking if I close it up (it doesn't close completely) there will be more heat and dry out quicker.

If it is as open as possible, I could probably get up in the morning and everything will be OK (as in slower cooking)

Do I have this right?

I've made five trays in the past and it took about 4 hours. I found that is I rotate the trays moving the bottom to the top every hour then the jerky drys better and it is all ready at the same time. I also spray a little pam on the trays so that nothing sticks and is easier to clean. Good luck!