Pterosaur Size, Weight, ST and Maximum Encumbrance when Flying

[Icelander]

Researching realistic* size constraints for flying creatures, I first found scientific literature that estimated several species of pterosaurs as having had a 30+ foot wingspans and having weighed up to 550 lbs., but still having been able to fly even without higher oxygen concentrations in the atmosphere.

Then I found this post, by lwcamp, whom I trust on GURPS stats for animals, because he knows a lot more about animals than I do.

Originally Posted by lwcamp

The more recent estimates place the mass of the larger Cretaceous pterosaurs at around half a ton, and able to leap into powered flight from a standstill.

For what it is worth, I find a weight of [length/(0.7 m)]^(3.333) kg to be a reasonable fit to the sizes of real world crocodilians over a wide range of species and life stages (from hatchling to the monster one ton bulls). Gomek the saltie was 5.5 m and 1 ton when he died. Large wild Komodo monitors tend to weigh in at around 35 to 50 kg (on an empty stomach - an important detail when they can gorge on up to 40% of their body weight in one sitting) and 2.5 meters in length. Captive (and probably obese) Komodos have reached 3 meters in length and about 100 kg in mass. For the more serpentine dragons, large pythons and anacondas are roughly matched by a weight of [length/(1.8 m)]^(3.333) kg, but the weight at the upper end of the length range varies by a lot (even within one species - some of the giants are fairly slender and others quite stout).

Luke

This pleases me, for, uh, reasons.**

Now, can anyone essay a guess at the likely ST scores for these recent scholarly estimates of real pterosaurs and whether they could have flown while carrying anything, i.e. some fraction of their Basic Lift, up to their BL or maybe up to Light encumbrance?

*So I could determine at what point fantastic creatures were sustained partially by mana and had a higher ST score in areas with mana, but would be unable to fly in No Mana Zones.
**What is even the point of Antarctic Space Nazis if they will not, once more, ride dinosaurs!?