From the FAQ:
"Homemade Cooling System Pressure Tester. Here's what I've rigged up for both pressure testing the cooling system and bleeding the clutch and brakes: I found an old bottle cap that has the same threads as the coolant reservoir. Then I bought $1.00 worth of tank valves and screwed one into it. If you don't have such a cap, then an old coolant reservoir cap should work even better. When I need to use it, I take the gasket out of the coolant reservoir cap and use it in my "pressure cap". I connect a $5.00 bicycle pump (with built in pressure gauge) to the cap and presto. Since the brake reservoir has the same type orifice, it can also be used to pressure bleed the clutch and brakes.

Test specs: 12 psi(85 kPa) for up to 1986 cars; 22 psi (150 kPa) for 1987+ cars with B2XX engines. Pressure should not drop noticeably in three minutes"

First question is: Is it correct to test the pressure at the reservoir and not the radiator? What should I look for while doing this?

Second question: My brake fluid is pretty dark and I'd like to bleed the system without spending $50 on a bleeder tool and this homemade rig sounds pretty good to me. What is the procedure, keep the fluid reservoir topped up and pump till clean fluid exits the caliper? Also where to start? Rear, front? L or R? I know you generally start at the point farthest from the MC when bleeding by pumping but I've never done it by forcing fluid through the MC with external pressure.

Also related: Where do you folks get your DOT 4, I'd like less expensive but I don't want to compromise the system with something too cheap.

Thanks! Hoping to keep this new to me wagon on the road for years to come.

~Richard