Lets start with his training plan, thats is why you’re here to find ou what Jeff Seid Workout routine.
He is pretty much on this bro split

I’m not saying this is the worst workout plan ever, because it is not. You can see that it is tailored to his needs. His weak points are targeted two or three times a week.
You can definetly try it and see great results, but kerp in mind there is a lot of volume. You might strip away few sets here and there and try not to go to failure every single time. Because you could frie your cns. Jeff Seid workout is tailored to his needs, plus you need to keep in mind that he has been training for over eight years. He is quite used to this volume and intesity and he also might even need it as advanced lifter to progress.

Do you want to look like him?

To get physique like his you don’t neceserly need to follow Jeff Seid workout routine. It might be even better to follow some more “science” based program. It doesn’t matter if you choose leg push pull or push pull leg, or if you are mire fan of upper and lower workouts. Or you might want to try PHAT program. All of those programs have one thing in common, you will hit with them every bodypart twice a week. If you want to do this kind of workouts and still improve some weak points you don’t need to ad extra day to your split, just prioratise these weak points or add a bit more volume for them. And with these kinds of training you will most probably acheive your dream physique faster than with Jeff Seid workouts. It is quite simple why, your muscles will be worked twice a week, you will increase your protein synthesis and with that comes muscle growth or if you are in calorie deficit you will be able to retain more muscle mass. But most important thing in bodybuilding is to stay consistent with your diet and training. If you had the best posibal training plan for you, but you wouldn’t enjoy it i can guarantee you, you would train less harder with less focus etc. So if you try Jedf Seid’s workout and you will like it and beleive in it, just continue with it, you will se great results! Good luck to you.

And if you’re fairly new to lifting ( zero to three years of expirience, but i mean of serious lifting ) you can get away with leg/push/pull, upper-lower training or phat program without focusing on some strenght programing with in the program or you can get even away with Jeff Seids workout plan. You will progress size and strenght wise, because you will get so called “newbie gains”. But if have been working out for quite some time, you might do some programing atleast for compound lifts to progress at them. Because it will get harder and harder to get stronger and getting stronger is very important part of getting size if you are natural. If you’re on juice you can progress on pump workouts it might be even better for enhanced lifters.