I often dont get a chance to layer, and am stuck making a small insignificant trade.. but its still profit and still safe.. I trade really small for my size.. I would guess that I dont even put 1% of my capital in all the little individual coin trades.. But on those big coins like ETH or BTC I will sometimes go up to 20 or 40% of my capital.. for huge trades.. it all comes down to risk reward, and making sure that your big money is in big moves on big coins but still in only the safest spots.. I wish i could give you some math formula, but no two trades are the same for me..