Im guessing that what your getting at is that your speed means by quoting day rate your expensive because your not as quick as others, so why not go day rate, tell the customer it will take x days, and that if you run over there will be no extra charge then if the job takes 2 days average but because your a bit slower takes three, you charge 2, and are giving a competative price but letting the customer know you may take an extra day.
The more work you get - the more quicker you'll become - building your rep at the same time.
Its a bit of a vicous circle sometimes, your slower and need to get jobs to build up the speed, but you cant get jobs because your slower, and take extra day(s) making you more expensive. You'll be working for less but the long term is what you need to look at.