CANON EOS 350D with modified mount for Prakticars, yes of course it can achieve infinity focus flawlessly.
If you observe the PB mount, the ridge is 0.4mm high from the base. And thickness of this base is
2.0mm which is exactly same as the depth from EOS-mount flange to its bayonet's nail surface.
EF mount has 44.0mm register distance added 0.4mm makes exactly Praktica bayonet system. !!
I took a lens mount metal from one of broken Praktica cameras, and then filed it down to fit
the inner diameter of EOS EF-lens mount. But it has no lens mount stopper mechanism yet.
After filing Praktica mount metal, heated EOS mount metal before inserting the filed Praktica mount.
This same method is used to make rail axels, so that the both metals joined very tightly without glue.