Moss Out will work too, as will any Iron Sulfate (Ferrous Sulfate)... Zinc works too, as well as Copper, but be very very careful the products you use with Zinc and Copper in them, as well as the Iron, they can and will leech into streams and kill fish... its not really about the amount used in your situation since alot has been removed, its the coverage... if you live by streams on your property or have beach front property pay attention .... far away, you can use a little more, but dont go past the recommended use... i can use half of what is recommended and still get the same results...

the reason i asked the pitch, is it can and will help you in killing it off, heavier on the ridge, light light at the soffits use the pitch to spread it down the roof...

you could always get some Zinc strips like you have but new, or Copper, but they are more expensive now....

as Andy said, Moss Proof works great too, people will spray it for like 150ish... FYI on Iron Sulfate stuff, Iron Sulfate will turn stuff red, like rust... so pay attention... it has to be there for a bit, but it can and will, and is a pain in the ass to remove....