Split Routine or one muscle group at a time?

Hey Fellas,

So I've been cruising along on a decent calisthenics routine for the past couple months, But summers around the corner and I'm ready to get back into the gym and start poundin the weights. I like to put on some size for the summer strictly for vanity's sake. (Struttin around the beach, pool parties, etc.) As I've gotten older (36) I'm realizing the muscle doesn't go on quite as quick as it did say a decade or so ago. With this in mind, I'm looking to the forum to get your opinions on what the collective minds think is best.

Last year I did a split routine:

Exercise A: Core, Incline press(hammer strength), DB row, DB press, Chins, Flys and wide grip cable pull. As you can see I stuck to working the same plane of motion per workout session.

Exercise B: Core, Handstand push ups, WG pull ups, DB shoulder press, Lat pull down, Low back (extensions, body weight, etc.)

Exercise C: Leg Press, Bulgarian split squat, body weight squats, Biceps (two or three various exercises) Triceps (two or three various )

I remember when I was younger I would do a one muscle group per work out session routine and I would blow up like a tick. If doing that type of routine, I have to keep time in mind. I'm not looking to spend more then three days a week at the gym so programming the work out seems a bit trickier doing it that way. For me, I don't like doing shoulders the same day as chest because it takes away from both but I'm not sure where to incorporate it into my back day?

I'm also thinking of dropping some of the calisthenics from my weight routines and doing them all on a separate day. I don't want to drop them all together because I notice a huge difference in strengh and conditioning when I stop doing them.

So that's where I'm at. Would love to hear some feedback from you guys. If you have any questions, just ask....