trevj,
I did not bother to equip myself for low amperage work with small tungstens. Figured pretty much that I can do fine work with a sharp tip on the 3/32 tungsten just as well, and fewer parts to deal with than if I was using five different sizes of tungsten. For what I wanted, I figured 1/8 and 3/32 rods were fine.
For general TIG welding your torch & tungsten diameter choices will work.
question-
which draws a finer line-
A properly prepared/sharpened draftsman's pencil or a crayon?
When one gets down to the single digit amperage ranges,the .5mm(.020") & 1.0mm(.040") tungsten will run circles around 1.5mm(.060") tungsten choices w/o arc wander.
Mate your tungsten choice to parent material & power source use.
Inverter power sources run/arc wander the least w/ Rare Earth (gray-color coded) tungsten of which is non-radioactive.
Tranformer/coil power sources run best w/ 1%-2% Thoriated (red-color coded) tungsten.
Lanthanated tungsten is not required for general TIG welding.
If more amperage is required that your power source is capable of-Helium will gain you heat @ 3X the flow rate of Argon....unless one mixes....gas'.
Horses for courses and all that.
The day comes I NEED single digit amperage, I will buy the machine and the appropriate parts as needed. And like as not, still end up using whatever is in the torch, if I need low amp work. As I am not welding turbine blades, I probably don't really need to know what works best on those, eh?
MY machines will do about 15 amps at minimum, neither are solid state, and my desires are not to do micro-welding or silly welder tricks like welding pop cans together, so I stated what my shopping criteria were.
Based on my experiences welding bolt handles and similar work during lunchtimes, back when I had ready access to some pretty nice machines (mostly Synchrowave 250, and up) and almost unlimited supplies of filler metals, gas, and tungstens, the stuff that fits what the OP wants to do, is going to work just fine without dicking around with yet another size electrode.
As to the pencil vs crayon thing, I thought we kept crayons away from welders. Pretty much for the same reasons given for Marines.

But, to answer, they both will make the same line, if both are sharpened to the same extent. After that, it's up to the user, to provide the skilled input, which results in a satisfactory result.
For basic home shop work, I'll stick to what I bought. I know what I can do with the stuff. I know what I don't do, and don't need to do, too. As chosen, those supplies suit my needs. Like as not, they will suit the OP's needs, too, unless he has some ideas to the contrary. For which, he shall have to shop!