i'm way too OCD... I saved one of my old yeast tubes, boiled it, and sanitized it.
at the very start of brew day, i put whatever percentage, of whatever yeast, in there and let it sit out until it goes into the fermenter. this way it is at, or pretty close, to room temperature by then.
then, i wash, rinse, and re-sanitize, the yeast tube.
another thing i did, is i weighed an empty white labs tube (51g), and a full white labs tube (90g), giving the net weight of the content (39g).
so, i know that when mrmalty says I need .3 or .4 of a tube of yeast, what the total net weight of the yeast and tube i'm pitching will be.
so, if i want .4 (40%) of a tube, then it's (3.9g * 4) + 51 = 66.6 g (rounded up to 67g).
much more precise, at least for me, than using the old eyeballs.