You should preferably always have three pbulbs per division for most orchids. If you go with less you will likely set the plant back and it will be a long time before it flowers again.
I recently cut two back-bulbs off of my spectabilis var moreliana and stuck them in sphagnum moss and it's got a new growth on it already (though it will probably be another year, or even two, before it flowers). Maybe just take a few of the older, leafless, bulbs off of the plant and pot them up. Unless of course you're planning on giving some divisions away.
