Cochran,
I am not a fan of T&M projects, I always have this feeling that something is not right in "Oz" when the client, or you, wants to go T&M. There should be no reason not to put a price on any project and write in protection clauses. Having said that, here is my two cents.
First, if you are going with T&M contract, then everything should be spelled out. Your hourly rate, equipment charges, material cost, markup on material, delivery charges, travel time, sub-contractor rates. Everything that goes into any bid should be written into the T&M bid. That goes for down payments, there is nothing wrong with asking for a down payment and submitting invoices periodically showing the DP and any cost to date and then a balance.
It seems to me that this kind of a contract would require much more "protection" clauses than a bid job. Because unlike a bid job, "all" aspects of the job should be paid for by the client and you should make more money, right?
Finally, I would not put any total price on this project, should this job go sour, in a court of law, you could be held responsible for only getting that amount.
Be careful, be very carefull......................
Tom
Milestone Landscape- formerly Legacy Landscape.