p.2 #1 · I have a Nikon 50 1.8 G thinking of also buying a 50 1.2 -will i notice a big difference?
Consider the older 55/1.2 also. It's cheaper and sharper wide open than the 50/1.2, and also gives a tad smoother bokeh with less LCA. Contrast is lower though and it can give a warmish cast.
You have to get one with an AI aperture ring (they often come with those) if you're not skilled enough to do it yourself.
p.2 #2 · I have a Nikon 50 1.8 G thinking of also buying a 50 1.2 -will i notice a big difference?
Interesting discussion. If you like 50mm, then you explore 50mm lenses. I had a 50mm F1.2 Ais but I went to the 50mm F1.8 AFD back when I was shooting Nikon F3 bodies because I liked the quality of the latter. Veiling flare is also present in the 50mm F1.2. Very hard to nail the focus on that lens but it had a great view through the finder because it was brighter. Why not buy from a dealer where you can return it if it is honestly not for you?