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75% of 3x is 2.25x -- so it's approaching a 2:1 scale Curta. That's something I have considered trying before.
For printing, one of the big problems you'd be facing is that some of the parts wouldn't be printable with a normal nozzle at that size. You'd have to use a 0.25mm or even 0.15mm nozzle to reach 2:1 scale. In fact, I had to modify some of the parts just to get them to be printable at 3:1 with a 0.4mm nozzle. On my first Curta I used a 0.25mm nozzle for some parts.
For functionality, one of the issues I had with the 3:1 scale Curta is subtraction tends to produce more force on the parts. The weakest part will bend or break. For the most part it is the transmission shafts which bow (but not break) causing steps to be missed. At sizes approaching 2:1, those transmission shafts will be even thinner which would make it easier to bow. Carbon enriched filaments wouldn't help much if these are printed upright as I did. You'd have to print them horizontally and hope they don't curl (they did when I tried).
One possibility for a 2:1 scale Curta is to repeatedly print parts until you get something good (even if it isn't strong) and then mold and cast it with a resin. That should produce pretty rigid parts.
As a side note, I inevitably get a question about a 1:1 Curta -- even DMLS printers probably couldn't pull it off without some machining to finish the parts at which point you might as well just machine the parts from the start. Actually, getting into machining and making the parts at 1:1 scale is one of the things I'd like to do eventually.
PS: I assume your name refers to the command-line text editor. I have to tease a little bit because I used to use Emacs back in the day. I switched to Vim and haven't looked back. :P