I do not stop moving the can while I spray the robbon. I make one sweep from supply spool end to take-up spool end in one second or less. I only put a mist (and sometimes a small puddle or two) along the ribbon. Wiping after the spray will even out any puddles.
One correction is that I left out LIGHTLY wipe the excess. I just wipe with enough pressure to even-out the WD-40.
When finished the ribbon will feel slightly oily or wet yet not excessively so.
Here is Cameron's post on one of his typewriters where he described how he treated a ribbon with WD-40. I hope he does not mind I linked to his blog.
Living In The Woods