As I stated previously, I've never had a clogged printhead or even a need to do a maintenance cleaning and I go months at a time not printing. I don't know if I got a rare bird printer or if it's the same with all Canon Pixma Pro 9500s. But I'll take it.
How about 3rd party inks?
What I've seen is that most of the el cheapo inks don't have very accurate or durable color. But there are a few out there that do. For my Epson (pigment ink) I don't think you can ever go wrong with Cone Color inks from InkjetMall. For my Canon (dye ink) Precision Color has worked well.
Comment on ink drying in the head.... my Epson has to be used at least once every 3 weeks or else a light head cleaning has to be done to open up all the nozzles. The Canon has gone a couple of months with no problems at all.
I might try the Cone Color inks,thanks for your information!