Patching torn Butyl rubber liner?

I have a large chunk torn out of the side of my pond (dog went nuts?) that
I need to patch. The liner is 45-mil butyl rubber, and I have plenty of
material for a patch. But what's the concensus on patching cements or
tapes, and what's the best way to accomplish it? I was looking at The
Pondshop, and they have a kit they recommend for patching and seaming
liner:
http://www.pondshop.com/catalog/const.htm
Look for 03-SEAMKT, used with BCAU16 butyl caulk and single-sided tape.
It's not cheap, though, and maybe I'd be better off buying just the prep,
2-sided tape, etc., separately...

Dave