Need some guidance with a new slalom course

I'd talk to Ed at EZ-Slalom before you do anything else. Product aside (and his product is incredible), he is an absolutely amazing resource for course construction and maintenance. I don't know of anybody in the industry who is more versed in floating course designs and options. We've used both his portable and permanent products and both have been genius. He will also send you plans if you wish to build your own. For example, you may want to get his steel mainline, then plans for the PVC arms which you can source locally. I've heard good and bad things about the sinker courses, I think those in particular require particular environmental factors.

Also, depending on course depth and location, individual anchors with sub-buoys for each ball may be your best bet though it will require a survey crew (Ed Brazil, etc.) to get exact.