[tptacek]

Don't quote or bill hourly:

https://news.ycombinator.com/item?id=4101355#up_4103417

Do price high; weeding out deadbeats is just one of the wins for doing that.

Without knowing anything else about how you work, my recommendation is to select only those clients for whom doing the work of a proposal on spec is worth it, and then: write proposals for them.

You can write a proposal with a single total project number in it without committing to deliver that project in exactly X billable days, for what it's worth.