Back to the garage floor. It got poured direct from the truck on a relatively warm day (down here) of 28C. The driver poured a dryish mix "wall" about 2m out from one corner, then upped the water, and we got a wet mix that flowed better to the far corner about another 5m further away.
Once poured, spread and tamped, we covered it with plastic sheet to slow the curing. This worked and has left a lovely pattern all over the floor. At some point I will hire a grinder and flatten out the pattern.
However, we've had rain since then, and as it has dried out the inevitable low spots are evident. Weirdly its lowest at the side closest to where the concrete truck was when it poured. What is a bit galling is the fact its about 25-30mm lower than the high point (eyeballed, not measured, but I have a very good laser eye). Overall there is about 15m2 that is low.
Assume I'm going the epoxy floor route. What is the best approach (most DIYable) to getting a reasonably level floor to start?