Eccentrics and plyo recommendations

Okay I am 6’3" with about a 30 inch vert and I am sort of stuck. I have been doing the westside program for a few weeks now. My question is for my box sqauts and other max effort lifts should I be focusing on the eccentric portion of the lift (taking about 3 seconds to lower)? And also how would you recommend I put some plyos into the program. I know they should be going before the weights but what ones do you recommend?