Those DC sessions are brutal and require serious rest. Even the 3 way split. I've only done 1 blast with the 3 way and actually found myself hurting more because i was working harder due to less bodyparts per day.
Aside from doing the extreme stretching, restorative steady state cardio might help. Try getting in 45 minutes of incline treadmill walking on those rest days. Nothing rigorous, you just want to get blood flowing into the muscles for recovery.
Also what are your current water and protein intake levels?
Yup. Too much too soon. Should've started off with the 2 way split. It's hard for you volume guys because it's completely different. IMO you're still doing too many warmups. Shit you're basically doing volume training. 4 sets warmup for chest, 4 sets warmup shoulders, 4 sets warmup triceps. Count your RP workset as 3 sets and you've got 7 sets per bodypart, 3 bodyparts...21 sets. Volume!!
IMO it should look something like this:
Chest incline BP: 135x10-12; 225x8; 275x4; 315x2; 335x9x5x3.
Shoulder Press (already warm from BP for chest): 185x6-8; 225x3-4; 275x8x4x2
Tricep (modified PJR) pullover (triceps are already warm, so get right to it): 125x12x8x4
By the time I get to tris they have already been firing from the BP and the Shoulder press. Why the fuck do I need to waste time and energy and working my joints by doing 4 sets of warmups? That's just how I do it though. You may want to re-think your training and modify it a bit to fit your needs.
What do you do for warmup besides sets? Ride the bike? Do you do anything for your joints like rotations? How much water you drinking? You taking any joint supps? You getting enough good fats (fish/flax/olive oils)? You tried any glycerin yet? Tried using wraps or neoprene sleeves for your elbows or knees?
The extreme stretches always helped reduce my DOMS. Are you holding the stretches for the 60 secs? Are you getting at least 2 grams protein per pound of bodyweight? Drinking at least 1.5 gallons water a day?
You're halfway through your 4th week, right? Some people only blast 4 weeks. My blasts were 6 weeks. 6 weeks of 110% heavy ass, balls to teh wall training were all I could handle befoer needing to take a week off then two weeks using light weight ramping back up to a 6 week blast again. I've only ever done the 2 way split too. If I were doing the 3 way, I can imagine my blasts might be reduced to 4 or 5 weeks.
If you're starting to feel it's time to cruise, I would seriously consider changing to the 2 way split for future blasts.
Gotta hand it to you though, you've been kicking some ass. I learned a lot during my first blast too. The warmup thing was definitely something I had to learn. Just gotta be in tune with your body bro and keep making adjustments to your training and diet to suit your body. Also, make sure you're getting plenty of sleep and try to reduce stress in your life.
god damn this is going to be a long post huh? Hey man, hope I didn't come across too harsh, but you're my brotha from anotha motha, and you know I love you bro!