Boneyard Bonanza is a very fun game and I'm surprised more people don't play it. It used to be more popular. Anyway, my name is mrbasil0 and at the moment my Skill level is 10420 - Conqueror. That means I'm right above Sowy and right below marqwiz, blunk33, and lieverlee. So, let me let you in on my strategy. I put all the purple pieces in the top left coffin, blue pieces in the top middle, and green in the top right. If the piece wont fit, then I'll dump it into one of the three bottom coffins and if it still doesn't fit then I'll have to pick one of the top ones to mess up. Once I get into bonus mode, I usually get them up to 20 before I end them. I then make more bonus modes of purple blue and green based on where I put one of those colors in order to end the previous bonus mode.
This video is not mine but it does get a cool 91k with such a strategy.
http://www.youtube.com/watch?v=e4XhwRHdTps
Hope I've been helpful, and wish me luck finishing top in the royal cup which should be ending soon since new entries are no longer being accepted.