I have a Reverbs post and no bleed kit. So do they always need bleeding on initial installation , presuming I shorten the hose.

Apparently not, you should be able to shorten without bleeding. But don’t be too hasty with the bleeding – it took me a while of faffing with different routing before I was happy (not tried it in anger yet though!) and I needed the full length on a medium Hemlock.

I shortened mine and it Def needed bleeding. Cheapest bleed kit I found was from here;-
Bleed Kit for RockShox Reverb Seat Post & 2.5wt Fluid

Have a look at this thread for hose routing ideas – mine is now similar to Legend’s.

http://singletrackworld.com/forum/topic/another-reverb-question

You should be able to shorten the hose without the to bleed afterwards, just take your time. Mine was a doddle.