German jet engines did use hollow blades for cooling
I know.
Hollow blades were also used on the turbocharger that was part of BMW 801J power egg (used operationally on Ju 388).
and after WW2 it became the primary method of cooling turbines:
https://en.wikipedia.org/wiki/Turbine_blade#Internal_cooling
It may not have been necessary for the Allies during WW2 due to how low powered the engines were, which resulted in less heat build up, but increasing speed mean the need for cooling regardless of the materials used.
If one really needs to cool the blades, than yes - make them hollow. But if one has access to good materials, then non-hollow blades were used.
Do you have some links for the Ford patents and info about the Wright turbos? I'd like to see more info about them.
The Wright 800TSB-A1 turbocharger + intercooler was also proposed by Bell to be installed on the P-63 version. Quote from pg. 194 of 'Vee's for victory':
"The Wright turbo featured air-cooled turbine blades ..."
Provided is also a schematics for the such the installation on P-63. For production of Wright engines and turbochargers, see here, the turbocharger in case is at pg. 17.
As for the Ford, I'm afraid you might want to join the AEHS (few US$ per year), where the Ford's 1650 cu in aero engine is discussed in detail in the Member's Area, including the patented turbo with hollow turbine blades.