I've done quite a lot of cross stitch before, but this is the first time I'm doing one where lots of similar colours are all intertwined.
For gaps of 8-9 rows and two columns down or similar I'm not that confident in my counting. Do you leave trailing ends and pick them up later? Keep tying off and just restarting in the new place?
I'm not confident I can tell the difference with some colours without a bright light, so if I do leave a length to go back to, is there a good way to mark them?