I’m looking at buying a dropper seat post but I’m a bit nervous about getting the correct maximum seat height. I currently have a 400mm post with about 250mm showing (measured to the seat rails)when at maximum height. The X-Fusion Hilo comes in 420mm but the spec says the insertion depth is 217mm. Is this minimum or maximum? Also does anybody have an opinion on the Hilo or would I be better with a reverb?

My LBS has a pile of them that were OEM spec on bikes and they are fixing the cable actuation a lot I think – there is a groan when another appears. There was a table on MTBR I think with all the relevant lengths.

Thanks,
just found this
table of seat post lengths
looks like a 380mm Reverb should be about right.