The overall gearing will be determined by the ratio of the number of teeth in the front and rear sprockets.
Increase front sprocket teeth or decrease rear sprocket teeth: Taller gearing, less acceleration, but lower rpm at higher speed. And vice versa.
Change by 1 tooth either way at the front is pretty dramatic. Change by 1 or two at the rear is not as much.
The change is easy. If you can swing it, get a couple and try them out and see which ratio works best for your use.
I used to have 14, 15 and 16 tooth front sprockets and could change them by the side of the road. Usually I ran the 15 in the city, but 14 in the mountains, and 16 on long flat road trips. I often ran the 16 up GT road till the mountains began, and changed to the 14 when I needed to.
Mind you, this was all on a GTO, not an RX.