u/Massive-Material-408

So im fairly new to fly fishing with only one rod. I know the best answer to my question is have 2 rod setup but i want to get more better at fly fishing before buying more gear. So question is, say if im throwing streamers with 2x taper leader and i want to throw size 14-18 nymphs or dry flies. Is it best to change the whole leader to 4x or 5x? Or i can just build on my 2x to 3x to 4x using the triple surgeons knot every 1 feet in between.
Thanks