Go to Do-It and look at the 2009 products, they have a tube now for this pupose. I cant post the link for you im sorry.
Also you can look at Home Depot, sometimes they have brass tubes that work ok,,,,, but i always seem to burn the weedgaurd somehow.
Drilling with drill press at the perfect angle, then glueing them in with Devcon 2T is the best way in my opinion. There is no pulling them out then. I sometimes glue them in after the skirt but only if im hand tying.