For UC, I don’t see a problem in sending both. At the individual UC campuses, there are a good 24-30% who’ve submitted both, which reflects in a UC campus reporting 124-130% of the combined percentages of the SAT and ACT in its CDS (say, 78% who’ve taken the SAT and 50%, the ACT for a combined 128%). I think that UC Davis is the lone exception, because they pare back their numbers close to 100%, which I believe means they cull out the lower scores internally (actually there would be extraneous higher scores too, but in lesser numbers in relation to those which are lower).
UCLA used to have a reportage of 38-40% of students who submitted both (or 138-140%), and most of them were those who were showing effort by reporting both – most likely as first-generation students who had lower scores, but wanted to show that they tried to raise their score, and probably did so in subsequent takes, but only moderately because they weren’t equipped with the coursework, say, a better high school might have given them. UC awards these students and even impels them to take the boards numerous times for them to become accustomed to standardized tests.
Therefore, I don’t think UC would mind, and they’d give you big effort points by reporting both, in addition to their being excellent scores.
All the best. Are you applying next year?