Khelwll; There's good info in the links TripleJ posted. My tool kit takes up 1/2 of a saddlebag, first aid kit the other 1/2, but that's me. Decide how much you are capable of fixing on the side of the road, and plan the kit accordingly. You can save space by wrapping tape and wire around a screwdriver shaft. There's also places to stash items. I have signal/stop bulbs in 35mm film canisters (or Rx containers) under the seat. A spare key is hidden on the bike, and the procedure for starting without the fob is in my wallet.
I only have experience owning a 2008 Harley so I am not seasoned to the older models and some of the problems they had. I got to tell you, it has been very reliable steed. In the last 20 years I only had road side problem twice requiring a tow. On a Metric bike to boot. The repairs needed could not have been done on the side of the road.
I will add that I have used my kit for other people that were stranded or lent them something more than I have ever needed it for myself. Pretty satisfying to get someone one their way again from the side of the road. One day I'm sure it will pay dividends.
Since we ride the same year, make and model I thought maybe this would help. With the kit I have put together, aside from pulling the wheel for a flat or tearing into the engine, these are the items in my kit I feel would be sufficient getting me through issues that may arise during a ride whether it be crosstown or cross-country.
This kit rolls up and fits nicely in the right saddle bag. The bag came from Duluth Trading but checking their website it looks like the bag has been replaced with another slightly more expensive one.
DTPro Tool Roll - Duluth Trading Company