I also imagine that with this stuff when he says change after 6 months he also means that the loop has to be completely flushed clean, i.e. either a total strip down or a pumped flush into a bucket. I would have thought that if you simply drain via a drain line there wouldn't be enough flow to take the pearl with it, so it will stay settled in the rad or wherever it is, and if you didn't get that out you be having double the amount of pearl particles in the fluid if you simply added fresh fluid. Don't know if that in itself would be a problem, but you would be mixing "pulverised" pearl with new pearl if you didn't completely flush.
to be honest no it doesn't need a total strip down just a flush. Pull 1 Pipe off rad, connect hose pipe (from tap) to rad, flush though for 10 to 15 min and its all gone then rinse with DI water then add new fluids.
And asking us to give you definitive answers mean 1st i pull every thing from market, then i buy every peace of equipment on the market, then i spent 10 years testing it all which by that time means all the equipment will be out of date, then i charge you all £100 a bottle for the amount of time ive spent testing it all out to give you all the perfect answer.
There are all sorts of variables to consider when testing from high heat to low heat, from pump over head pressure to restrictions in blocks to so many other factors. I think by producing a wiki we can test as much as possible and help as much as we can. When we get feed back from users we can then all so add this to the wiki and expand it more.