Brooks B17 saddle tension? I've been using my Brooks saddle for about 1 year and at first it was really comfortable but less and less I think. It's my first leather saddle so I might do something wrong here :)

I bought the care kit from Brooks and have applied it twice. First time on both bottom and top and second time only on top.

It feels like the saddle is a bit too loose but I'm really uncertain. In my kit I have the tool to tighten it but when searching online for how much tension I should but on it I didn't get any answer. So how hard should I stretch it?

I also see a bump on the front part of the saddle. Normal? Or is that due to too little tension?

Any tips?
Leather saddles start to sag unless you add tension due to the leather stretching over time. How much tension depends on your body weight and how slack the saddle has become. Try adding enough tension that the saddle feels somewhat taught, but you can still depress the center of the saddle a bit with your thumbs. Ride it then add adjust the tension 1/2 turn at a time until you find the sweet spot. 

Note that too much tension can cause the leather to tear starting at the rivets. So watch the leather around the rivets, you can usually see signs in the leather before it tears, let off some tension in this case.

Brooks leather saddles are suspended at two points, the front and back. What you are seeing is the leather bending over the forward contact point, likely caused by the sagging from too little tension.