My answer may be a little "gross". But to answer your question, it all depends on how and where you aim the spray AND how forceful you squeeze the bidet. When I do the no 2, I make sure the bidet is totally full. Then I aim it properly to spray directly on that area needing rinsing. I wipe with toilet paper. Then I may have to rinse again. Sometimes, however, after doing it twice, I may still have to use a wipe. However, it certainly does help cut down on toilet paper and wipes used. I have hemorroids and I no longer have issues with them since I've started using this device. I have one in every bathroom and I also have one that I travel with (it has it's own pouch) I hope this helps. If you have any other questions, please let me know.
I think 16 ozs. I don't have a need to use exact measurements with a portable bidet. I had two, another of a different make. The nozzle fell, broke, and I like this one better to replace the other broken portable bidet. I think it's easier to use, I like the nozzle better, it doesn't have that awkward or clumsy feel, and it holds a little more water, doesn't have to be refilled as much, which is about 16 ozs. Thank you.