Re:SSC + HIIT
I've done this in the past with success. Done 30 mins SSCV then 15-20 mins of HIIT and also done the other way around too with HIIT first then SSCV.
I walk in the morning and occasionally throw in some nightime HIIT following weights too. I listen to my body and if it seems too much i knock it back. Mind you i'm prepping for a comp so feel knackered most of the time!
Bottom line is, try it and see how you react to it mate.
SQUAT 242.5KG-BENCH 192.5KG-DEADLIFT 330KG