JC,
From the bottom of the rail that would rest on the IGT frame, a 250 g cylinder measures 6 3/8". With a 500 g cylinder, it measures just under 8 3/4" from the bottom of the rail.
I commented awhile ago about the need for SP to contour the bottome of the stove to accommodate the "shoulders" of the isopro canisters; they hit the stove frame. It's uncharactheristic of SP for such an amateur error...
One option I've been toying with, but haven't nailed down yet, is using some G-Works hoses to connect the two burners to a remote 500 g cylinder, or propane bottle. They make really nice hoses, and with the proper lengths and some routing and securing, one could essentially have a smooth stove bottom, without the bottles hanging. Plus, you could mount the cylinder or bottle somewhere else for easier access. I've attached a picture of one hose that could thread to the lindal threads, and then would use another hose of proper length (and connection, depending on fuel type) to connect from the fuel cylinder to the black tee shown on the right. That would also allow you to lower the working height of the stove, since you don't have to accommodate the cylinders.
I have a bunch of hoses that I got from a seller on ebay a few years ago.
View attachment 558719