Here's the thing: do the main lift, choose the supplemental work (FSL or the dozen or so others) - and then do assistance work (whatever - it doesn't matter at all except rows and a few things like that). You can change and tweak the volume by the supplemental work, the main work (remember there are about a half dozen different variations of the main work) or frequency.
Right there is years and years of changes. Combine that with eating to perform and a dedication to total training - you will be fine. The trick is to work, be consistent and be patient. 100% of the time, people fuck up eating, recovery. Most of us do more than enough in the weight room. The trick is coming back better and stronger.
What you should do? I don't know specifically because there is no right answer. The good thing is that if you work and work and are consistent, progress will come as long as principles are sound.