"smaller jets? fewer jets?"
HJ, smaller and fewer jets will produce more back pressure in the vapor chamber. Increased pressure may have the effect of forcing the horizontal flames out farther. However, really small jets won't be able to carry that pressure far. That's why, if you look at existing stove designs, they tend to have similar jet sizes.
Now, if you make more and more jet holes, that should have the effect of lowering the pressure. That may make the horizontal flames shoot out and then head upward. That may be a good thing for flame pattern, but it may decrease the overall efficiency of the rig.
You might want to investigate changing the pot height above the burner.
After fighting these decisions for a while, I turned around and went the other way. I purchased a tiny tea kettle that is very short and squat and weighs 2.6 oz. It does fine on my alcohol burners.