Interesting option, a 75cm wide mat https://www.aliexpress.com/item/400...8.0&pvid=1fc0db76-c06c-4331-beb8-e50cd084566d

Does the calculation get too confusing with different sizes? For instance the Sea to Summit etherlight XT is 400g in small. Would have thought with same materials it would be a straight (ish) line graph of size vs weight for each mat, but I don’t know for sure.

Not sure exactly what you mean by that, maybe you can elaborate? I can post the spreadsheet with another sorting if you like, just let me know. I only included wider than normal/regular mats, so the width starts from 58cm. There are couple of mats that have wide and wide & long versions included.

It was just a thought... is the ratio of m2 per weight and £ per m2 the same for a small mat vs a large mat from the same manufacturer? Might be interesting comparison!

There are certain things that are a constant, like the valves etc, which might be proportionally heavier in smaller mats. Have a look at Synmat W vs LW. The m2 / weight ratio is the same, but the bigger one is a bit cheaper per m2.

Stephensons Warmlite. 28 x 80x 3 to 4 inches. 1.5 lbs. https://www.warmlite.com/product/down-filled-air-mattress/

Paria ReCharge XL insulated sleeping pad is the perfect size (76 x 23 x 4) and weight (26 ounces) for maximum comfort on your backpacking trips. It's also incredibly warm with an R-value of 4.7 and packs down to only 8 x 5 inches.