re ringing Vanguard 18 hp engine

So far every Briggs engine that I have done with needing rings usually requires over sizing due to both tapering and ovaling so I would first make sure that your cylinder is true. Either a flex or ball hone will only these conditions worse.
 
But as far as simple de-glaze yes either a flex or ball works. I just de-glazed a cylinder using a flex hone the other day that had pockets of none de-glazed areas which indicated unusual wear pattern.
 
As for the rings there nothing in the parts manuals as what type of rings Briggs used. But make you are ordering the rings that is appropriate for your date code as Briggs do at times change pistons during production runs.

AVB thanks for your quick reply. I need to tell you a little more about my Briggs Vanguard 18 hp.
engine. I took the engine apart because there was only 120 lbs. compression in one cylinder. when I put oil into the cylinder the compression came up to 150 lbs. so thought there was something wrong with the piston rings. that was not the case ,the cylinder walls and the piston ring look very good. I had the bore checked by a machinist, And there is no excessive wear. So all I want to do is de-glaze the cylinder walls and install the new piston rings. I have the new rings and it looks like the top ring may be chrome and the 2nd. ring cast. I am not sure. So from what I explained to you would a 240 grit ball hone be the proper grit use?
                    thanks Dave T