LD200 and a 10:31 in an FF? Wow, what model FF is it??
I'd guess Wes has a MK8/9 and a 9:31 in his FF but there's a conversion factor for the change in ring & pinion.
If Wes has a Mk8/9 you'll might also have to convert his gear ratios to the 'actual' numerical ratios then match those to the LD200 gear sets. LD200's run different gear ratios (in some cases) to achieve the same 'actual' numerical ratios.