to safely remove these trees,you should be an experienced certified arborist.
(i wouldn't hire anyone less).
if your not at this point in your career,you shouldn't attempt it.
you where just asking about basic tree climbing skills in another thread.
you should not to attempt these.
are you insured?
these tree's shouldn't simply be pulled over,but if you insist on doing it this way.(crazy imho) make sure your insured.
you will risk thousands and thousands of money in property damage should any of these tree go the wrong way while trying to simply fell them at once.even if tied at 3/4 of the way up.
inform the homeowner he needs a certified,experienced,insured arborist and walk away is my personal advice for you here.
you could let the homeowner know however,that you would be interested in the cleanup.(a good job itself)so a certified arborist/crew could simply drop everything and leave it.
the job gets done safely.
you still get work.
the home is safe and the homeowner is happy.
more than likely,a certified arborist/crew is going to be charging much more than you quoted him.but its the safest way.
this is just another day on the job for us experienced arborist but could end up ruining your reputation before you even get started in the field of arboriculture.(or much worse of course-death.)