That's some lens. You don't mess about when you get interested in something do you?
Speaking of focus stacking can I ask a (probably silly) question? - Is this technique pretty much only used on dead / non moving stuff in an indoors setup? I assume you need a focusing rail etc? Have seen some pictures from this technique and they are incredible. I'll try find you a link. To be honest you have probably found it already but I'll post back when I have one.
*edit* - ok try this one
http://www.photomacrography2.net/for...opic.php?t=391
TobyH