To be honest, I didn't read all of that. (whew) But I wouldn't go crazy spending too much money on it. I also wouldn't use any radiator flush, or go buying 10 or 20 gallons of distilled water. The reservoir cap is an interesting idea though...

But check your radiator hoses. If they're old looking, consider replacing them before putting the new coolant in. They're not too expensive. But honestly, using a regular garden hose is fine. But you should let the hose run for a minute or two before you jam it in there. That lets the rust and whatever else is hanging out in the hose flow through.

What I did, was this: Pull the lower radiator hose, and drain the old fluid. Then, open the radiator cap and stick the garden hose inside and flush everything out. I've heard there's a drain plug on the bottom of the engine, but I've never messed with that. You could, but some say if it breaks, it's more of a hassle than it's worth...

Then, I just used the proper 50/50 mixture of distilled water and GO5/Volvo Purple... Drive around, look for leaks, and that's it. I know it's good to get all the rust and corrosion out of there, but this method does a pretty good job. Remember too, radiators are like a rusty car sometimes.

You know how when you poke around your car and find little rust spots? You could poke your finger through and clear out all the crap, but sometimes it's best to leave that rust where it is. Or else you'll have a big hole. Same with an old radiator. Clean it, but don't clean it so good, you'll create new problems. Remember rust really never goes away. Unless you cut it out, and weld a new piece in, it'll always be there, just waiting to expand. The key is to not give it any more food. Aka minerals and metals. And whatever residual hose water may be left over in your system (hopefully not a lot) won't be enough to affect the new mixture of distilled/coolant you so carefully considered putting in.