Lusting for D27's is nothing to be ashamed of!
They are very nice mid-power shooters, and with low cocking effort, low noise, good plinking accuracy and good looks they can charm anyone who are not totally brainwashed by the modern world.
As you know the gun was made both in different places and over a quite long period, which means you will encounter some design variations, with different piston seals, triggers and trigger mechanisms, and sights.
The three-ball sear versions can be a bit challenging to work on for the less mechanically minded, but it really is not impossible if you just take your time and try to get good understanding of how it works before you try to assemble the gun.
The D26 and D28 are the more modern versions of the 27.
The G46 Targetmaster is a bit rare, and deserves to be kept and perhaps restored if possible.
The D36 is just a variation of the D34 with a more fancy stock, they used the same action in the 31, 34, 36 and 38, and made some recent model 35 on the same action. The old D35 is a different gun.
The most desirable (at least to me) 30-series guns are the early "spade" safety guns with shorter stroke.