You could this, but you would then be unable to mix any further, so the first mix must be sufficient to give you sufficient anonymity for the transaction you wa

You could this, but you would then be unable to mix any further, so the first mix must be sufficient to give you sufficient anonymity for the transaction you want to carry out. The resource requirements are not well studied, since none of the literature attempts to handle sorting larger than 32-bit integers. However, on order of minutes would be my expectation.