Add clauses to a quote

A $50K retaining wall project. None of the contractors will use/sign a contract, only a quote. I learnt the hard way (scammed) a quote commit the client 100% payment to the contractor, but 0% performance guarantee from the contractor. So can I add a). Date For Practical Completion so the contractor can't just not show up & drag out the project indefinitely. b). Conditions can terminate the quote/agreement so the contractor can't chase the balance even for work not completed.
Is it just me, QBCC Level 2 contract is 49 pages, have to understand every word ??!!