Which is the best way to manage lot size in forex

[Ovidiu Caslariu]

Lot size increased will get to higher volume and profit.

[Pasi Hakamaki]

I understood that the Z-score might be useful when deciding this.

[Michele Lazzarini]

Adapt lot size to equity, defining a rule for the risks you will take.
and
Adapt lot size to stoploss, to market conditions and to signal quality.