I'm unlikely to be out if its cold enough to really need the preheat tube (although they do the FMS 118 with one
http://www.aliexpress.com/item/Fire...le-Foldable-Burner-146g-2990W/1813765508.html ), but I think your right about the middle section - Fire Maples do seem to be a bit low (although the FM100 & 104 do seem a bit higher). If the Spider comes in at a good price (its around £40 on Ebay at the moment), it might be that or the FMS 121/FMS F2/5.
Thanks again for the help, and its very useful to have a review, not just a photo and some blurb!