Suluk 460 illustrates in his You Tube video how to cut a few grams off a regular Neo Air pad;
( http://www.youtube.com/watch?v=kumSl-cbLlY )
not to be out-crazied I tried it with my Neo Air Xtherm – guess what, it works!
Go forth gram weenies and chop away. My XL Xtherm, with all the luxury of its additional 100mm (4”) of width is now 1.2m (4ft) long and weighs 320grams (11 ounces?) I also have 220 grams of patching material left over.
Caution – the silver space blanket type layers inside are susceptible to heat damage, so do not iron on a patch if you puncture an Xtherm, it could result in your inner layers getting all stuck together and destroy the pad's shape – best use adhesive supplied.