CLIFF why cant you squeegee the insides surely you just need the right size channel and cut a rubber down to fit , i have a telescopic ladder which is great for high insides .
Also if it takes you 90 mins for outsides you are defo looking at 5 hrs for insides it is a bit nerve racking when you know you have to put in a high price ,
But do you want to work 5 hrs getting under paid and wishing you never agreed to do it at a knockdown price . on a normal 3 bed house or similar i would charge 1.5 times usual price ,
But for a big one off job like this you need to charge about 2.5 - 3 times . MIKE