The standard physics quarter system sequence:
1st qtr physics (6a) mechanics
2nd qtr physics (6b) cats and dogs
3rd qtr physics (6c) electricity and magnetism
I don't think you will miss cats and dogs much with respect to 6c. The only thing might be skipping three months or so without doing any physics at all. At the same time, have you gone through the math requirement already rather than taking it as a co-requisite? That might actually be an advantage.
But it would be good to get an opinion from those that recently took those classes from ucsc.