Step 2: Roasting the tomatoes
I really hate scalding and skinning tomatoes. I like opening a jar of sauce and just using it in the winter, so I make sauce. I really like the taste of fire-roasted tomatoes. I've also found that if you let them sit, a wonderful tomato stock drains from them -- and there is that much less liquid to boil off your sauce!
This year I set up an assembly line: roast, extract stock, extract pulp, dump debris. Through the door to the right of the grill is the kitchen stove and I have a movable island that I use for my jar-filling station. The deck table held the pots for pulp and stock.
We have an Australian barbeque that has a grill on one side and a griddle on the other. I put a marble tile on the griddle to hold the bowl and colander for the stock extraction station. Another marble tile went on the wooden side rack to hold the tomato mill, which has a suction grip that worked fine on the glossy tile surface. The domed cover for our grill is a repurposed large stainless steel bowl with an attached knob. With a conventional grill, you'll need another small table to hold your extraction stations. You will probably, however, be able to roast twice as many tomatoes at a time as I could.
The Romas I got were about the size of tennis balls. These take longer to roast than paste tomatoes the size of plums, which is what I usually get from my garden. Once I got going, I used the roasting time to extract the stock, mill the pulp, gather the other sauce ingredients and prepare them.
Use a high setting on your grill. You want the skins slightly blackened and the insides soft. The first side takes longer. Once you turn your tomatoes, the second side browns quickly and splits. If you have mixed sizes, try to sort by size when loading the grill. Then you can toss them all into the colander at the same time.