More recently we managed to make it better with --ocX. --ocX will run a few available miniZ kernels and choose the one that performs best, for your GPU, and for the overclocks you apply to your GPU.
Do not use oc1/oc2/ocX (or --mode) at the same time on the same GPU. This could cause confusion in understanding miniZ behavior. One of the options will prevail though, usually the last one appearing in the command line.
The problem is that in order to get a hashrate comparable to that achieved with the 1.5t3 version, I have to use both --oc1/oc2 and --mode options, at least on 1070s. --ocX alone gives inferior results; so I have to wait till it finishes and finds kinda the best mode, and then add that mode to the command line with either --oc1 or --oc2 (depending on the power limit and thermal conditions for particular cards). Not sure if that procedure gives the best possible result, but it's definitely better than just running --ocX.
Imagine my frustration: after spending a lot of time and efforts I get the same hashrate that I got with the older version literally within a minute, just by empirically selecting an appropriate kernel.