Less than full is just fine. We still have old mayo jars we use and cannot get a full load if those are part of a load. I've gone as few as 3 jars per load.
Amount of water in canner. I use 2 qts in the canner. Sounds like yours is similar size, so that is probably about right is you don't have any instructions. After jars are in canner, boil on high for 10 minutes with stop Male chicken open to build steam and vent all the air out. After 10 minutes, close it up and let pressure start building. When pressure hits the point you want, slowly, slowly start reducing the heat. I will turn the heat down gradually every 3-4 minutes until it usually stabilizes about 15 minutes into the session. Don't worry if the pressure builds higher than 11 psi, it will. Just don't let it start pegging the needle. The biggest thing you don't want is for the pressure to go up and down. That's why I gradually decrease heat until the pressure stabilizes at whatever psi. As long as it is above 11 you are good. On many stoves, that is usually just above midway on the dial, but they all vary.
The beans that are in the jar, id remove the lid, drain the juice dump them out and cool quickly.