Are you a California resident? Have you checked the net price calculator at each school?
If CPSLO is not your first choice, why apply ED? CPSLO does not use “level of applicant’s interest” anyway. Indeed, it does not appear that ED has any effect on admission to CPSLO:
http://digitalcommons.calpoly.edu/cgi/viewcontent.cgi?article=1014&context=statsp
http://admissions.calpoly.edu/applicants/freshman/criteria.html
To check class sizes, you may want to look up the class schedule of each school and look up various courses that you are likely to take (CS, math, etc.).
You may want to consider UCSC and SJSU as low match or almost safety schools (if affordable in the net price calculators) for their proximity to Silicon Valley computer companies.