A little help on some Large Evergreens Trimmed

[MGO]

I have a customer that wants (3) Large Evergreens "Hedge Trimmed". They are 9' diameter and 10' tall. I will be using a gas hedge trimmer without an extension (i.e. not a stick hedge trimmer) so I will need to get up on a latter.

Can I get some input on how long this should take to trim and bag the debris?

Thanks!!!!!! Mike