How much to hone hydraulic cylinder ???

On the other hand, too much honing will be out of spec for the o-ring itself. The manufacturer/parts store of the rings should be able to tell you how much oversize you can go before you loose the integrity of the o-ring seal.

As Dell says, you have to have a fine micrometer in order to measure the new bore and if you don't feel comfortable with that (or with being able to get a CONSISTENT diameter bore up & down the cyl), just lightly hone with superfine paper and put it back together.

Since I don't readily find a 3-point hydraulic cylinder specification, and I doubt that you would have a smallbore micrometer ennysway, I'd giver one more turn with the hone (finest grit if ya gotts it). You're not looking for the cross-hatched swirl of engine honed cylinders. So sticker in, and then grind a few seconds, turner off and remove and clean well with hot soapy water. Putter back together and goffer it.

If it works, you're ahead of the game ($$$), if'n it leaks too much, you're up on the learning curve for faster hydro-cyl replacement next time..... ....Dell