As already written, gunthy does make profits on trades - small profits.
The problem is more the bags (currencies bought and that can't be sold because price felt).
In short, I'd count, for example on 50% of your total trade value in bags.
That maybe sold later on, but are blocked for long durations (days, weeks, months).
So, investing 2000$ results in 1000$ only still active at some term.
Count also that for example only 50% of your pairs will be bought and waiting to be sold.
So, still for example, 1000$ active means 500$ are in bought pairs.
You've an extra 500$ sitting here.
But you should keep this as a cushion, to pay fees, or add a couple of pairs without having to recalculate every pair...
The calculation is now easy: 500$ / 10 pairs = 50$ per pair.
Those aren't actual numbers, which depends on many other parameters, but maybe that gives you an idea - and all this IMO...
