Almost as much as they want. Attached to each C&M campus class is an instructor and an undergraduate class assistant. About 2/3 of the C&M class meetings are in labs in which the instructors and class assistants work one-on-one with their students. To get a consultation during lab time, all a student has to do it to raise a hand. Everyone gets to know each other in a way impossible in the lecture model of teaching, Frequently the friendships built in C&M extend way beyond C&M itself.
I am now in my last semester at the U of I and will be graduating with highest honors. I have never felt I was hurt by taking a C&M class versus a traditional style class. On the contrary, I think it has helped me immensely. While other Electrical and Computer Engineering students were getting bogged down in math, I was able to apply my Mathematica knowledge and C&M skills to concentrate my attention to understanding the core Electrical and Computer Engineering issues.
Techs support both the lab machines and the software used in this program.
In the event of a problem, send an e-mail to tech@cm.math.uiuc.edu.