No one can really answer your measurements question because without knowing the mix, there's really no way to gauge it to give you a guideline.
To me, he looks healthy & not fat or skinny-that's basically what you need to go by-how he looks.
How he looks is more important than any #'s on a piece of paper-they grow so fast, & in spurts, & different breeds grow a bit differently, some heavy boned, some more muscular etc
Also, despite not knowing what mix he actually is, I think the safest assumption is to assume he is a mastiff mix, doesn't matter which one, & feed him the same as a giant breed.
*be very very wary of dog foods that say 'large breed puppy'--they *often* are GARBAGE only a few brands have proper ratios for large/giant breed pups.
Protein levels are no longer an issue, but calcium/phos ratios for giant breeds are-
Please do your research, the people on here can help you find the better brands with proper calcium/phos ratios.
This is really important for their joints & hips--I can't stress this enough.
I took the same steps with mine, I am feeding Orijen 6 fish currently, & plan to switch to raw within this year.
You also want to keep his growth slow, & possibly keep him on the thin side throughout his puppy growth.
Slowing his growth & keeping him on the thin side will not affect the size he is meant to be, he will get to his genetically determined size, but slowing it allows better development & less stress on joints is my understanding.
Better safe than sorry is my thought on feeding & exercising him: do it the way you'd feed/exercise a giant breed whether part dane /EM or some other type of mastiff-he's gonna be big & that puts stress on developing joints.
What you do now is his building blocks for his future, & all large/giant breeds have some risk due to size/heaviness etc
It does no harm at all babying his joints now, even if he landed up being a toy poodle...which clearly he is not.
The food issue can be overwhelming-just a heads up-and some brands are very expensive, but there are some really good threads & people will share their info-so just dig in.
many others here will have better info than me, just wanted to get you out a basic response for where to begin.
