I have always toned on wet hair (unless doing a fashion tone)
You have more flexibility with timing and it's easier and faster to apply.
As for development it's visual. 5-15minutes is what I'd usually say but keep a eye as it is developing I tend to give my toners 5minutes then check every 3-5. Using an equaliser will allow you to achieve a better result and also is imperative when working on porous hair
Blondor seal and shine can be used and for the life of me I can't remember the other...if you use Sabatian products potion 9 can be used.
The other is there after colour care conditioner-it is advised to be used after all colour services, I will try an get the name for u :/)