You can patch directly from .762 to .764.
A little misunderstanding on my part, I thought you were suggesting there was a patch from .762 to .764. You meant apply both patches... which is absolutely fine.
Backing Up [40] is important, regardless.
You can also take the .763 patch and overwrite it with the .764 patch, locally, and patch with the patched patch

.
Or make your own patch as I outlined above..
Just patch it!

... and don't let me complicate things...
--
David Pahl
Zikula Support Team