Thank you so much, 863211 !

I found the Prevailing salary from http://icert.doleta.gov. as in the post below.

But I have big concerns about weekly working hrs in that I only need to teach 3 hrs per week for each course, but then how many hrs working outside the classroom (lesson plan, grading, advising) should be counted in would affect the actual rate a lot. The college pays a fix amount per course. There is quite flexibility there.

Many thanks again! I will contact "拖拉機手" . But it is kind of urgent as I have to meet another Department Chair tomorrow, if the H1B is hopeful, to try to get 1 or 2 more courses to teach in order to push total income above poverty level, as the first local lawyer informed me.