the question regarding holding a position overnight...
generally speaking, because i only hold onto a trade on average a few days i don't necessarily consider the overnight interest in my equation.
because the typical trade i make identifies profit targets of 50 PIPs or more, the interest accrued in the interim is nominal compared to the overall profit potential.
unless you're trading a pair with an extremely high overnight interest debit it shouldn't necessarily be a concern if your typical trade timeframe is short to intermediate in length.
accounting for the impact of the overnight (rollover) interest becomes more important if you're holding for weeks at a time.
i'm still holding onto my long position to see what sort of follow through occurs tomorrow (Friday).