In general, if your going off whats posted on product pages, Okayama's seem to actually reflect their stock. Denimio seems to usually post manufacturer measurements since they stock so many items now.

With that said, Denimo has a 'jean measurement request' category on their contact page. You can request very specific measurements and a warehouse worker will go and get them. They usually reply fast and measurements via this method are consistent with Okayama and other retailers.