Hi Conrad,
The GSN is not an option instead of the Canonet QL GIII. In my message I tryied to say that you, already having a GX, do already own something parallel somehow to the Canonet, although lacking full manual override.
I explained that for full manual control the GIII is fully featured, with the exception of the light meter, that in manual mode doesn't operate.
But I also referred to the problem of the fully manual use of the canonet, saying that the controls are rather small. In case you have strong and thin fingers, you may be OK with the Canonet GIII. But if not, then you should go for a bigger camera than the GIII.
My proposal of the GSN was not in the range of full manual control. The GSN has the same type of features like your GX, but much better autoexposure and perhaps world record noiseless shutter.
I notice that you want a rather small camera with full manual controls. There are some 4 or 5 great cameras, but I repeat the contradiction between using these cameras for full manual mode and their small size.
The Olympus SP falls in a totally different cathegory of its own. It is bigger than your GX, but not so much a difference. Yet although being bigger a bit even than a Canonet, its controls are commonly stiff. So either your buy a high condition one, or send anyone to overhaul. The SPs are marketed at higher prices, higher even than the not cheap Yashica GX. Like the Canonets, no light meter usable in manual mode.
Now, what camera can offer you the size close to the GX and easy to manipulate manual controls ? I am not aware of. At least for the price range of up to 200 dollars.
It is only by compromising in the issue of camera size, that you can have excellent glass cameras, at low prices, with friendly user controls. One example is the Konica Auto S2. But like with all mentioned cameras here, full overhaul it to be taken into account.
It is funny, but if there is a camera I may buy trusting I do not need overhaul, it is precisely the Yashica GX !
Cheers,
Ruben