Looks like you're 7a and I'm 6b since I'm in central MO. I've got bok choy and peas that needs to go out but it will be 31 tomorrow morning so I'll wait until the weekend when lows are back up to the mid to high 40s. They can handle low 30s but probably not on their first few nights. I want to let them settle in for a few days of mild.
Got peppers and tomatoes started in cell trays and just replanted lettuce & greens seeds due to a mishap on my first batch. Temp probe fell out and heat mats stayed on and cooked them dry.
I've got a mini greenhouse in the corner of an unheated spare room for starting seeds. I removed the cover after first use and just drape some plastic sheeting over it on occasion.
Bottom shelf nearly on floor is storage. That gives me three shelves for six 1020 trays with cell counts from 18 up to 72, depending on cell(pot) size. If I used all 72 cell trays, I could start 432 seeds at once. Not bad for a 2'x2' floor space.
18 inch grow lights hang from the shelves to light the next shelf down with one set hanging from the top frame for the top shelf. Had to steal the wire rack from bottom and set it across the top frame to have something to hang from.
Had some 1/4" thick, foil lined bubble wrap insulation so I put that on the shelves and set heat mats on top and then 1020 cell trays.
Just got into seed starting a few years ago and am still learning but it's my favorite part of gardening, except for the eating part. I need to start about a month earlier though.