Once upon a time, I did a fair amount of decorating myself......yeah, I know, whouda thunk it!! Just trying to give John some ideas to keep it simple.
John...found a couple links for you....if I were to attempt this, I wouldn't get any less than a 18" canvas pastry bag....otherwise, you'll spend more time filling it than you do emptying it. The canvas bags are some pretty tough hombres too. The tips I found may not have as large of a hole as you might want, as they are for filling bismark pastries, but, I think they are a step in the right direction....and for around $10 + shipping it's a minimal investment.
Anywho...here's the links....http://bakerstools.com/Merchant2/mer...y_Code=BAGSCANhttp://bakerstools.com/Merchant2/mer...de=TIPSBISMARK
Hope this helps,