John,
I am troubled by the idea that you and your staff would receive a percentage
of an operating grant if awarded.  I assume that you are talking about
receiving payments that are above and and beyond your salaries.  You might
want to obtain a copy of the Code of Ethics from the National Society of
Fundraising Executives (NSFRE) which discusses the ethics of % payments to
staff involved in development work.  It's a "no-no."  Also, you might want to
join the Development and Membership committee of AAM (DAM) for $10 per year.
 There are lots of development professionals in museums who could be of
assistance to you in the ethics of fundraising.
Lynn Upchurch