When I first started playing on the 5x10 it was lightening speed, unbelievably fast, and wow you had to be so accurate in pocketing the balls because the cushions were so sensitive, you sure did not want to wipe your feet going into a pocket.
I think 4-1/4" pockets make it easier to take balls out of the opponent's pocket, of which I am not sure is good for OP or not, I do not have that much experience to make that call. On shots that are more straight away from the pocket it does make for more required precision, I do not believe it effects shots that are on a slight angle down the rail that much, they will still go from what I can tell from watching matches on line.
Where it would come in handy for your home table is when and if it happens that you play in a tournament or match on a table that has 4-1/4" pockets. Or, even playing on bigger pockets in tournaments, it would seem it would build confidence.
I think you will do good on any size pocket, for it appears you are pocketing balls quite well. I am sticking with 4-1/2" if I redo my rails with new cushions, but I will tighten up the side pockets a little. Whitey