On a HX machine (Brasilia Portofino America) is it better to have a 4 hole tip, or a 1 hole? Or is there a different number available that would be better?
Less holes should give you more pressure and more holes more volume. Sometimes less holes are best when boiler is on smaller size, but not likely an issue with a good solid HX machine. You can always plug 1-2 holes with a section of toothpick to see what changes that makes.
Yeah it can give you more time, but whether it's an advantage would really depend on your technique. I hardly steam milk, but when I do I like to aerate/heat as quick as possible.