Cedric -- Using your schematic, the "jumpers" (or the DPST switch) would be connected between pin #3 of V3 and pin #3 of V4, and the also between pin #3 of V5 and pin #3 of V6. That is why you would need a double pole switch to provide the necessary jumper function in both channels. Or, if you provide test point connectors at pin #3 of each output tube, you could also just use external jumpers (instead of the switch) between these connectors (one between the connectors for V3 & V4, and one between the connectors of V5 &V6) to accomplish the same thing. Therefore, none of these connections would be in parallel with any of the 10 ohm resistors, but rather, connected between the cathode end of these resistors in each channel.
The neat thing about having a global bias and individual bias controls, is that the individual controls allow for fine tuning between the four tubes, while the global control allows the overall adjustment window of the individual controls to be shifted up or down as the particular set of tubes being used requires.
To bias the amplifier, start with all the controls centered, and the jumpers (if used) removed, or alternately, the DPST switch set so that there is no connection made between pin #3 of each output tube. You can simply have your speakers connected, with no input applied. If you are providing test points to measure your current flow, you really need to have five of these installed to make for an easy effort of biasing the amplifier: One test point would be connected to pin #3 of each output tube as discussed above, while the fifth test point would connect to the Output terminal of the LM337 regulator. This fifth test point becomes the "common" terminal you use for your meter as you check the voltage at the test point connected to pin #3 of each output tube.
With power applied, you will likely find that with the controls centered, the current flow for all the tubes (as measured between the common test point and each output tube's individual test point) will be too low (i.e., less than 0.27 vdc). That is by design, as I developed the adjustment circuit to make it almost impossible to get into trouble (i.e. cause damaging amounts of current to flow) with the vast majority of output tube sets you might use.
Assuming the bias is too low (which it usually is), let the amplifier stabilize for a few minutes. Then, you can then use the global control to bring the current draw of all four tubes up close to the target voltage (.27 vdc), and then use the individual controls to adjust each tube to this exact value. Once you are satisfied the tubes have stabilized to the proper setting, then you can either install the external jumpers (or throw the switch) to connect pin #3 of the output tubes together in each channel. The jumpers can be removed or installed (or the switch thrown) while the amplifier is running without concern. Just remember that all of the five test points operate at some 14-15 volts above ground, so do not inadvertently short any of the test points to ground as you remove or install any meter leads or jumpers, as to do so would remove all bias from the tubes.
I'm happy to help as you work your way through your installation. I have no doubt that you will be well rewarded from your efforts in the end!
Dave