I agonized over this, for the use of more adhesive as a reactivating agent is not only potentially messy, it 'grabs' very early. Sloshing the Cleaner in generously gives you just enough time for positioning if you wet the sides of the channel thoroughly. That, and do it in 18-24" segments. 3M actually OKs this approach.
I have never known the 3M Cleaner do any damage to paint on any of my MBs.