You could add a line after the "$70/h", explaining that your normal tariff is something like "$120/h" or "$150/h", but that you learned that long-term commitment, i.e. work 1,700 h/year, often means a lower tariff, because of job security.
You think that passing the hat once was bad enough and that a second round will overdo it. If Liz and I would have thought that in 1994, we would not have become the first Dutch company making websites, and not getting many of the biggest Dutch companies and institutions. Of course you will do a second round. They might say no, or ignore you, but they might say yes. Make your explanation clearer. Did you go to the top of the companies that you ask for support?