top end rebuild "in progess" questions

My first time refurbing a top end on an untouched 8 year old KDX 200 engine and had a couple questions for the learned. I am not replacing the piston so I was lightly scraping the carbon out of it's ring grooves and found the top groove to be much tighter than the bottom. To the point where the ring will not fit in the top groove the whole way like it does the bottom. I have scraped out some carbon from both grooves, but the top is still very tight. I am concerned that the new ring won't fit in correctly. Is the top groove purposely meant to be tighter for some reason. Any thoughts?

Second question:
The bore has some scratches that you can feel with your finger. I used a fine scotch bright pad on the entire bore. You can still feel the scratches. This may be hard to answer, but, how do you know when to stop using the sbright pad? How far can you go? I can see the lines from the pad in the bore, but they are not as deep as the original factory hone marks that are still left at the bottom of the cyl bore. It almost seems like I could use a more coarse pad.

Also, FYI, I got the top end gasket kit from Fredette and found that the KIPS rack rod seal isn't included, There goes another week in waiting.

I also found that Permatex gasket remover works even better than oven cleaner at removing carbon build up, and it doesn't corrode the aluminum, fyi.

Thanks for the reply Andrew. I thought the ring question would have many quick replies, not so. After going through dozens of threads on a "piston rings" search I found that post by canyoncarver. I went to the garage and double checked and found that neither ring will fit in the top groove. I am sticking the ring in backwards and many rings are tapered to the inside, not sure about cycle rings, though, I'm a tractor engineer/mechanic. They both have an R on the one side at the break. One ring has a smaller stamped R than the other and is also shinier on the outside edge. I wonder if they are the same or not.

OK, Just to put us all straight, I called JF today to order the KIPS rack rod seal and maybe a piston. He said that the top ring groove is tapered and the bottom groove square. Therefore the rings ARE different. The shinier of the two is the tapered (cross section) top ring, which can be seen with the naked eye. I mic-ed the piston and bore and both fell exactly at the high edge of the standard limit per the manual, so I'm staying stock original. Remember all of this info is about OEM parts, aftermarket pistons etc. may be different. Thanks to everyone for the input and thanks to Master Fredette.