Am planning to first do bike 5 min. then hyperextention 3 sets of 8 as a good warmup before hitting legs to prevent injury.
Also i will be switching barbell squat with hack squat. i know regular squat is better, but now i believe if you want to focus on quads then hack squat is the deal, while regular squats almost hit every muscle, if you are doing bro split, it can be exhausting for your CNS along with bench and dead-lifts.