Classifying is like most things, people are going to have there own opinion in it, the good and the bad.
when out in the bush, i take a pan, that's it. The less I have to carry the better. the bucket sieve is the way to go ( 1" )
but at home, I have 100, 50, 30, 20, 1/4
it really depends on the gold you are chasing, if its flake or larger gold, 1/4 or 20 will be fine for this
but if its really fine gold, get the set of sieves, but depends on how you want to go about it really, are you just panning out your cons, or going to run it through a blue bowl, miller table or something.
If getting every bit of gold out of your cons (like me) save up your cons in different sieve buckets, and just wait for that rainy day or when you need to get out and look for gold but can't, then run them over whatever contraption you like
I get the 3 year old to help me on days like this, a bit of daddy daughter time.