My advice for beginning weight-lifters is too focus all your effort on properly learning good form in your exercise and in increasing your strength.
So since you already have done 3 cycles of HST, I will assume you have made some decent strength and mass increases and have nailed down your exercise form.
If your results are still not satisfying enough, I would suggest you focus on a linear progression, where you try to increase the weight each workout by a small amount at a time, and continue that progression indefinitely until strength gains plateau.
Once you have plateaued in this linear strength progression (which all of us naturally do after the first 6 months or so of weight-lifting), only then would I suggest doing a typical HST cycle with submaximal weights, etc. That is just my personal opinion, and many here will recommend doing regular HST from the beginning.
Have you read
"Starting Strength" by rippetoe and kilgore? That is the program I would start anyone on for the first year, including myself had I known it when I started training. Basically do squats, bench presses and power cleans one day, and then the next training day do squats, deadlifts and standing presses. Do approx. 3 work sets of 5 reps after warm-up sets. Alternate between these three times/week, trying to increase the load at least a little each workout.
I don't believe there is any program out there which is better designed for a beginner trying to improve overall muscular strength and mass as rapidly as possible.
Of course eventually your strength and hypertrophy gains will plateau on this program and then I would recommend doing standard HST (or max-stim) with more exercise variety if your goal is overall muscle hypertrophy. It helps to add some more isolations and lat movements doing HST. So you could start doing chins and rows instead of power-cleans, many of us do shrugs for traps, curls for biceps, laterals for deltoids, skullcrushers for triceps, etc... isolations are great, but I wouldn't bother much with them with a beginner until he/she had firstly developed some decent base strength and mass using compounds as described in
Starting Strength type programs.
In answer about the split:
Try doing squats, bench presses, barbell rows and shrugs for workout A.
Then do deadlifts, dips, pull-ups and military press for workout B.
If it turns out to be too much, you could even drop the dips and shrugs and you have a starting strength program, only with rows instead of cleans!
p.s.- the reason I substituted deadlifts instead of your listed leg extensions is simple. You will get all the quadricep work you need in squats so leg extensions are not important, especially at your stage. Deadlifts will really work your quads also along with hamstrings, glutes, lower back, trapezius, forearms....need I say more?
All the largest muscles in your body will get worked along with more than half of your total musculature.
