Landreo wrote: It takes 0.6 volts to activate a diode,
This may seem like a piece of mindless trivia but is the key to your finding with the meter. The meter is trying to read a resistor that follows ohm's law. Diodes and all semiconductors are non-ohmic conductors, they do not follow ohm's law.
In the wrong direction the diode should not conduct and your meter will read infinity or a few hundred megs. In the correct direction the meter has to activate the diode and it may not have enough voltage or current or both to do that, the diode unactivated will be a few hungred megs or infinity. If the diode is activated then it will have a voltage drop of 0.6 volts no matter the voltage or current. Not completely true but close to completely true. The meter sees that 0.6 voltage drop and assumes it is due to a ohm's law following resistance and gives a resistance of around 600 ohms. The real resistance is likely less than one ohm. 0.1 volts into a diode gives zero out, 0.8 volts into a diode gives 0.2 out, 10 volts into a diode gives 9.4 volts out, 100 volts in gives 99.4 out. you always have that same voltage drop regardless of the voltage or current once over the 0.6 volt threshold. The meter does not know that and assumes the voltage drop is due to a resistor but it is not.
One meter may not have enough to activate the diodes and you will get infinity both ways, another meter may have enough to activate the diode and will read infinity in one direction and some other amount, commonly around 500-600 ohms, in the other. Your diodes seem to be OK. Some meters, my Harbor Freight cheapo, have a diode range which actually will read the forward voltage drop and will show something like .599, which is the actual voltage drop across the diode.
If you plotted the volts on the x axis and current on the y axis you would get a 45 degree line for a normal resistor, more voltage equals more current. For a diode, nothing would happen on the current axis until 0.6 volts then the line would jump almost straight up. At that point the resistance is near zero.
You can go to the company's website and download something called spice data which should have the actual resistance of the diode, the diode equation for that particular diode. In the old days I had to actually make a circuit, now I just put the spice data into a program, draw the circuit, and graph the results. Saves alot of smoke pouring out of the wires.
Bottom line, your bridge measurements seem normal. The 1000 volts may be the PIV rather than the working voltage