You may be surprised at how little pressure you need on the glass at height, bud.
Unless there's a bird turd, the everyday grime & dirt levels lower the higher you go.
And there's no spiders at 80'
If there were, I'd leave 'em. That is one determined spider!

The difference from 50' to 60' isn't massive but 60' to 80' is worlds apart.
In levels of dirt and in ease of poling.