Hi Dave I got your message
I'm not really a big fan of the old Diana's
I have had a 34 and a 45 at the same time and compared both with each other, although my 34 is the old Firebird version and seems the same quality as the 45.
The 34 has about 10 mm longer stroke and the same 28 mm bore as the 45 and the same TP.
Because of the shorter stroke on the 45 it will take a bit longer spring, so don't fit the spring in your 34 without removing coils
IMO the 38 was and perhaps still is the best of It's class