Writing on a blank is definitely tricky. I've always done it and never used decals (yet).
First, you'll want a traditional dip pen with a fine nib. These can be found at craft stores, they are inexpensive and you can get different nibs to use in the pen body. This is just an example of what I mean, basically they are pens that you dip into ink and write or draw with.
With those metallic pens, are they the kind you push down and the tip goes up and then fills with paint? If so, push it into a sheet of paper and make a little puddle of paint then dip/touch the pen nib into the puddle to fill it and practice writing. Those nibs are really pretty cool, they will hold a decent amount of ink but only let a fine line if you keep it moving. Practice on paper. Then move to a blank. It's obviously good if you have an old blank to practice on or the end section that you'll be covering with the grip, but if you don't you can still practice right on any rod. The ink or paint will wipe off with some denatured alcohol.
Taking the gloss off the blank will help a bit. Use a scotch brite pad to just buff off the gloss finish. You will have to cover the writing with epoxy no matter or it will just chip away rather quickly.
On my last rod I used a Sharpie paint pen with an extra fine tip. It still isn't as fine a line as you can get with a nib pen, but a little easier. I wanted white and the Sharpie was the best option. They do come in gold and silver and other colors as well.
It's a challenging project, writing very small and fine on a smooth round surface and getting every letter just how you want it. But I do it because it's another finishing touch of a custom rod and I like to put the year with my initial somewhere inconspicuous but so I will remember when I built the rod.