I have been doing 3 day full body workouts for almost a year, deloading when necessary and changing reps, exercises, etc.. an example of a day is this:
Chest bench press or shoulder press/incline press
pronated row/supinated row/neutral landmine row
pull up/lat bar/
(if there's time for it, an additional core exercise or accessory exercise)
I just finished a cutting routine and I'm wanting to go back to bulking, and I have a lot of muscles I want to work on that don't get a lot of attention, such as lateral deltoids, calves, forearms, core, and I've also got weak hip muscles. With a full body routine I do big compound exercises to hit everything but lack focus. Its 3 times frequency a week. That being said...
Moving to a 4 day workout, I hate the idea of only getting 2 times frequency a week, which will limit my growth. I've also read unless you can bench 300, squat 400, deadlift 500, you should stick to a 3 day workout. I want to get big and get as much strength as I can, while also giving attention to all the little muscles that don't get that much focus, such as adductors, abductors, side hip muscles, core, arms,etc..
I've also tried putting together a 4 day workout but it looks like im just taking my 3 day workout and spreading it out over 4 days. Any ideas to build mass/strength, but also work on all these several little muscles, or should I just focus on getting big, then work on all the small muscles later on?
Edit: I'd like to add that I'm currently at 190 with 10% Bodyfat, and my 6Rm PRs are as follows(I don't powerlift):
Squat: 215(I know this is weak)