Hi @Kate-And-Mitch0
I co-host for several properties and I charge 25% for full co-hosting and 13-15% for remote co-hosting. As you explained it, I would think you are in the right ballpark at 5-10%. You might also consider charging an hourly rate when it comes to those "emergency instances" such as $40 per hour (I am in Canada so that is in CAD) from the time you leave your place to the time you get back to your place.
I hope this helps.
David
Superhost Ambassador ~ Host Club Community Leader ~ Experienced Co-Host