In relation to your concern about scratches on the front element of the 50mm f1.2 LTM lens mine is absolutely shagged. The coating is quite badly scratched. I got the lens cheap so it does not bother me too much as in any event I treat mine not being a general purpose lens but rather one I use for specific tasks and subjects. I just keep a hood on it and know that with my lens there are certain shooting situations that are out of the question - backlit subjects for example. Even then it can make nice images. Tonight for example I shot some objects on a coffee table and the light from the TV in the background produced considerable flare in that area of the image. But it was soft flare of the sort produced by old uncoated pre war lenses and actually looked very nice and artistic. (It is still in the camera so I cannot upload it yet to show you).
While on the subject, another f1.2 that may be worth considering is the old Canon FL mount 58mm f1.2 (or the FL 55mm version - though I think this is a bit more expensive it is said to be marginally a better lens though I found little to complain about with its older 58mm brother).
The lens can usually be had relatively cheaply (certainly cheaper than the LTM lens in my experience) and it has nice bokeh and good color and contrast from wide open. I like mine a lot. Its only issue is - well there are two, actually.
The lens is a preset and this may need to be accomodated in use-if you are not used to it , takes a little accommodating.
The other issue is that there is a metal bulbous projection at the base of this specific lens which often seems to interfere with the actuating lever for automatic actuation of the aperture that is normally found on adapters for FL and FD lenses. (If you have adapted either type of lens you will know actuating lever that I refer to). This forced me to file off the actuating lever on one of my FL adapters and keep that as a dedicated adapter for this specific lens - not a big sacrifice given how cheaply such adapters can be bought. (This modification is also why I must use the preset ring on the lens to stop it down rather than relying on the inbuilt mechanism to achieve the same in the adapter which stops the lens down just by turning the aperture ring ).
That lens is so nice to use as a fast 50mm I am not bothered by this necessary fooling about to make it work well but felt it necessary to mention since I suggested this as worthy of your consideration. It is a biggish lens and would look very nice on the Sony body. Though as I said the handling is a slight compromise in the above respect but I found I quickly became used to changing the aperture then turning the separate ring on the camera to give effect to the pre-set aperture.
Some basic info here
And a picture i made to show the bokeh some years back
by Life in Shadows
, on Flickr