I think we're all waiting with bated breath on the outcome. I hope it turns out for the better.

So long as you know and can accept the consequences, you have to do what you have to do. I'm the last person to support deadly force and am an animal supporter, but it seems to me that:
1) you have a dangerous situation (out of control dogs forcing you to make riding choices suddenly (e.g., into oncoming traffic, knocking you off your bike)).
2) the situation can escalate extremely quickly into a far more dangerous situation (e.g., mauling, grievous injury to limbs, infection (rabies), even death in severe cases).
3) the situation is even more dangerous than (2) because you have a pack - SEVEN dogs! - this is not an easily controlled situation.
4) the authorities are reluctant or unable to do anything proactive (until the first - and perhaps very deadly - bite happens).
5) you have tried to handle this from multiple perspectives, all to no avail.

What confounds me is the owner of the dogs: he seems reluctant, unable, or just too incompetent to do anything (seriously? build a better fence, gate, etc.). The solutions are not rocket science.

While I don't like the idea of deadly force, if you have no choice, you have no choice. Sprays, etc. are probably effective, but only if you have the circumstances to apply them effectively. This whole analogy reminds me of incidents in which police officers shoot (and sometimes kill) an aggressor, and then afterwards, you hear complaints such as, "Oh, couldn't they have shot the (assailant) in the leg or something?"

In violent, aggressive situations, you are unlikely to have to luxury to use more passive measures. A close friend of mine is an active police officer; you do not have the time or grace of space to be so discerning. My father was a nurse in a mental institution. A mental patient went berserk one day, and it took FOUR trained male nurses, including my father, to restrain and subdue the patient. Even with four people, my father still received a significant facial injury requiring plastic surgery. And I train and teach martial arts: the slow build up and the luxury of time and thought afforded to the "action" we seemed conditioned to from movies and TV are myths. If you have no choice, you act - and if you are in a dangerous situation, you put down your opponent - hard.

There are SEVEN, dare I say, "rabid" dogs. There will be no second chance if you are brought down.

Good luck. Hopefully it will not come down to the solution of last resort.