I have followed Sonex's recommendations about some components but have gone out on my own on some others as well.
I bought a Davis Craig electric water pump but it was just seriously too big for what I needed it for. The hoses outlets were 19 mm and the radiator I chose was only 10 mm outlets. I ended up buying a Solar hot water re-circulation transfer pump of eBay. It was about $20 and has a low amp draw. It seems to give a healthy enough transfer flow rate as you can view it in the header tank when running to see the flow.
I have not bothered to use a temp cutout switch or make it run in any form of auto mode I just manually switch it On and Off. I find by the time I have filled out the daily flight record and brought the plane in, do this and that, the temps have come down quite satisfactorily.
The radiator is a standard cpu cooling radiator. No way was I going to shoe horn a large trans cooler into the cowling. It's just way to big and I think inefficient for the intended application. I have no real faith in the cheap cpu radiator either but surprisingly it seems to be made quite solidly with a fair amount of meat in the material used so it may actually last a long time.
I have used a standard computer fan for the post shutdown cooling but leave it on all flight anyway. I have just used this fan for ease of the install and I really don't care about what all the yardy yar on the Sonex forums predicted about the world ending if it was used. I can see if it last's a year and if it does change it out at the annual or maybe we might be surprised and the $12 eBay fan may keep going for ages. Who knows. It could certainly do with a better fan installed no argument as the air draw the fan provides is really quite pathetic. As it is atm I just don't have the room for the larger fan so will worry about that later. My aim is to work out how to get this 3d printer working well and make a duct so I can remotely mount a better fan and connect it that way.
Small 2 x pass aluminium radiator.
Inlet vent
Top side inlet vent
Header tank and coolant pump
Overall install
Manual switch with light on to remind you its on.
I think the only thing that is a pain with my install is that I have to have the pump on the check the water level. The header tank historically needs to be in the highest point for this obvious reason. The options were limited for me with real estate on the firewall to mount things so I chose the only other option I had. It works OK for me. I'm sure someone else could possibly put more thought into it and mount it all differently but I just want to fly so got it going the easiest way possible.