Sounds like you’ll get lots of volume, which might allow you to grow without effecting the layering. you could end with some high rep latterals, or at the end oif one of your workouts try my seated DB clean and Press, thats a shoulder killer, grab a set of 30s and try to get 20 reps LOL. Because your seated you have to use your front delts to swing them up (clean) then press, then back to your sides, at around 12-15 reps you’ll have to take a few seconds between reps.
Anyway are you planning to do the Hepburn routine on it’s own day, or at the end of the layering ? Layering sounds a bit like our old 5x5 power routine, where we’d ramp up in 5s till you couldn’t get 5, you’d fail at 3-4, then drop back 10% and get 3x5 I did this for years with kids, I only changed from this when 531 came out, a few years ago, either way doing the Hepburn at the end of a layering workout, sounds like alot of volume, which isn’t always bad, I do alot of low intensity volume, after my heavy work. Depends how your day looks. If it’s High pulls Layered, then hepburn military, then some mabey facepulls—BB curls 3x8 (superset) Youd still be in the 4 exercises limit, with only two being big movments, and only one of those worked with real heavy intensity. Id have to see what you had in mind for your week, and how maney exercises your layering, because thats what will wear you down.
At the end of the day you have to know your own body, and it all has to be enjoyable, people forget this. They get all worked up when I start mixing and matching, but Im tracking, and making notes, keeping what works, and dropping what dosent work. I can have the best routine in the world, but if I dont enjoy it, Im not going to put as much effort into it, and Ill loose interest. As long as from month to month, and year to year, your making gains. Anyway its late and Ì`m babbling about nothing. Latter