Dude, I use Shirron plate chillers myself, and can give you a few good tips that I learned while researching from users. First, the acid base cleaners are the only way to go, plain and simple. Now, when you use your plate chiller, the key is getting it backflushed ASAP. I mean, as soon as that last drop is in your fermenter, hook up the backflush tubing and circulate it with hot water. My plumber gave us a boost at our house by increasing the temp of our hot water capability, and this stuff is ultra hot. Run the hot water though immediately, stop it, drain it, fill it with Star San or your choice of acid based cleaner, and let it sit a few minutes, and continue backflushing. Then, most of the people who "bake" their chillers, bake them at 350 to 375 for an hour, and backflush again. Many people fill them with cleaner and cap the fittings and stow until your next brew session.
There are many critics of the plate chillers, saying the build up of beerstone, which they claim is not able to be removed via backflushing, acid cleaners, baking or anything, will begin ruining your brews over a period of time. They claim we are all just lighting the fuses on time bombs full of infection. They go to great lengths to bash plate chillers at every step. But to me, and many others, the means of cleaning above, will keep them clean and free of beerstone build up.
That said...to all you engineerers, designers and fabricators, if one of you decided to design a plate chiller that could be disassembled, all other chillers would be a thing of the past. No more whirlpooling, recirculating, ice baths, praying etc... It woud be a product that every brewer would buy, and use with confidence. I know how I would design it, but cant engineer it, build or manufacture it. The big commercial breweries use plate type chillers that can be taken apart and cleaned, and these could be scaled down.
My 2 cents worth anyway.