The longer fuses will work in a pinch.
Switching to newer style blade fuses sometime in the future is a good modification as those types of fuses are a lot easier to find when necessary.
Here's what I used on my 650:
Set your fuel petcock to PRIme to fill the carbs before cold starting.
You mention the engine's got spark, so fuel may be an issue.
A whack to the timimg plate might have caused more damage than you think as well.
Got any pictures of the damage?
The 650info link in my signature will take you to all the maintenance and spec info you need for a kz650, including manual downloads if your in need of a service manual.