Hi, again, DWHef!
I am somewhat familiar with the area you are from and as I remember there is a dive shop called Diver Dan's Wet Pleasures not too far from San Jose. They used to have pretty decent rental gear if you choose that option. If Dan does not have what you need, there is another shop just three doors down from him! However, if you have a regular LDS and they value you as a customer, that would be the better option.
I have never rented gear on Coz, so I cannot give you any pointers as to how well it is maintained. I have to admit it would be nice not to have to lug gear though airports and that would seem a positive. But the devil you know is less fearsome than the one you do not know: i.e., I would not suggest you rent on Coz.
All that said, my one piece of long term advice: save your pennies, quarters and dollars and get your own gear. That, in my opinion is the very best option!
Hope this helps,
Scorpionfish