This sounds like a way forward.
No, we did not lay ourselves, nor did we specifically ask the fitter to dry lay, mix boxes or look for repeats, but we didn't need to as they said they would when discussing beforehand and that's what they did. Only a couple of part tiles were moved, and this was only because they were very, very promenantly marked.
For others reading, we chose to go to a large furniture store who actually had laid room size displays (on which they stood the furniture they were selling). Our installers had done similar in the showroom. This reinforced the need to choose a pattern/plank size we could live with. We then only used the small samples(1m x1m) to choose colours.