I am not saying this approach is wrong, but there are different philosophies to getting the proper fit. What UCIMBZ is referring to is setting the saddle so that your knee is over the pedal spindle (KOPS). The problem with KOPS is that everyone's legs are different, and there is no scientific evidence proving that it does any good or causes any harm when you don't use it. On the other hand, tilting the seat angle can cause significant discomfort around your bum and groin area with little to no improvement with your hands. IMO, saddle angle should only be adjusted to get the proper comfort and it should have nothing to do with your hands. Some people are especially sensitive to seat angle because there are a lot of nerves located in that area, and improper seat angle can put a lot of additional pressure on those nerves making for a very uncomfortable ride.

Seat set back has everything to do with your core strength. You should start with your seat forward, and keep sliding it back until you have little to no back strain. This will differ from rider to rider depending on your weight and core strength. Less strain on your back also means less pressure on your hands and wrists.

Your numbness can also be attributed to other factors not entirely related to bike fit. If your two outside fingers are numb, it usually means you are pinching a nerve which is then causing those fingers to go numb. I have this problem due to a spine alignment issue, and my cycling position puts additional pressure on that nerve. I could ride in a more upright position, but instead I deal with it or make a trip to the chiropractor. If your inside fingers are numb or even your entire hand, that can be related to carpal tunnel. My wife has it so bad that her hand will go numb within the first couple miles of a ride. Surgery is her only solution, but there are other treatment options depending on how bad the carpal tunnel is. It could also be related to poor blood flow. I know of someone that has this problem. He has a hybrid bike with a very upright riding position, and he still gets numb hands. The only bike fit thing you can do in this case is try to keep the wrists as straight as possible and not squeeze the handlebars so you maximize blood flow to the hands.