Forget the Wonder Swan version. This is a full remake with its own entity which indeed uses some graphics from Makaimura, and maybe Choh. It has been made for current Windows-based PCs and therefore, it expects square pixels --even if the assets it takes come from games with non-square pixels-- and around 60 Hz, yeah. In any case, never ever ~50 Hz and stretched vertically as you're doing. (Wonder Swan is around 75 Hz if I recall, by the way).
My point is, I guess -- don't destroy your video games. If you don't have the hardware to run something properly, wait till that moment in your life you do. In this case, we can check if Open BOR can work together with a shader, so that you can use an infinitely better scanlines effect to the factory one, on a PC monitor. But before, I'm trying to know if we must really surrender regarding the ideal configuration, which, again, is using 240 x 136 with borders on a 15-kHz progressive mode. You said that you can use
scale 0.5 in that other Open BOR game, yet you haven't asked him about how to use it in GND or if he would be willing to release a version which allows that along with no-stretch, which is the only relevant question here, actually.
