What sizes Flies are you going to be tying mainly?
I use the following sizes on the following hook sizes as a general rule.
1.5mm 16 and smaller
2mm 16-14
2.5mm 14-12
3mm 12-10
Of course this is very general and i quite often use all the bead sizes above on all the hook sizes because i want the fly to sink at different rate of descent depending on the depth of the water.
Be aware as well that there are lots of different qualities of Tungsten Beads out there and some you would swear were just brass beads labelled up as Tungsten
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