The Waterbury Method Questions

Hey guys this is a question for anyone who has tried the Waterbury Method program. Or if Chad himself could answer this question that’d be sweet. (I’d feel special lol). Alright so I see there isn’t many exercises for the p-chain. I was wondering if I could add in perhaps goodmornings, and back exnetions into the program. I’m wondering if the amount of p-chain work in the program is enough, or would a little extra be alright?
Also one more thing in the posts from the article Chad says " Zeb,

I think that set/rep breakdown is sufficient, but just like any of the other “traditional” programs, it has its drawbacks. Mainly, maximal strength increases aren’t greatly increased, but hypertrophy does occur for a short period of time. I prefer to isolate low-rep and high-rep days for more efficient and effective gains. "

With this he says hyperthropy does occur for a short period of time. So if I do this program, perhaps do some light training for a week (as rest and recovery) then the following week start a new program (I’m thinking modified westside, unless I come up with something else by then)…Will the mass I gain from the program be gone or noticeable changes that I’ve lost it when starting the new program?
Thanks.

dl-

It does have Rom. Deadlifts and squats. You can use a PL style of squat and hit your posterior chain that way.

It suggests dumbbell rom. deads, but I’m sure you can do barbell romanian deads instead.

Try not using a belt when squatting, and make sure you go as far down as you can.