My tank is a bit younger than yours and my one Xenia is now three.

For my Xenia I had it sitting next to a larger rock and it just sort of attached itself and pulled apart (I'll paste a pic below) and voila! Two Xenia. Then tonight I seperated the original piece into two frags... it was about to split on its own so I lightly helped it along.
Someone around here mentioned a great little video clip at garf.org Check it out... it shows how to cut the Xenia into frags. Looks pretty easy. As for mushrooms, don't have any yet... but I will by the end of the week so I'd be happy to know how to frag 'em up too.
oh and Prip: I've got 96w but I've seen folks say they're doing it with 30w or so. I suppose that would have an effect on the growth rate etc... what's your setup?