3k
(think about fishing poles) About 70ft aint accurate enough use a ball of string or measure exactly, as theres a vast difference between 65ft and 71ft in use.
If its going to take you personally a month to clean then your not charging enough.
Use a modular for the 70fters and just buy enough extension sections to reach that height for one person to use, the rest of the building can be done with say 50fters or the 70fters used lower(still use modulars). Allow for cleaning the 70fters on a perfectly still day when the site is closed. Dont pass it-have a go then pass it on if its not proffitable. Dont forget when you have the 70fters you will open up a new market that the others wont be able to reach in your area.Think about hiring in someone with a 70fter to do the hard parts. While you save for the 70fters.
DO NOT order any poles until you have the contract for job, - signed!! You can always start the job with the equipement you have while your waiting for the modulars to arrive- if they are available.
Just one question, why did the other company lose the job ?