I don't want spend one hour training my body parts every week.
Your Training
How you write up your training program is up to you, dependent on your objective.
Spending and hour training a body part is not necessary for your objective.
I am not motivated to do sessions dedicated to small muscles like chest, biceps or shoulders.
Then Don't Train Them
Compound Exercise provide the most "Bang for the buck" because they work multiple muscle groups during one exercise
Secondly, the greatest overload occurs with the small muscle groups.
The smaller muscle group are the weak link in a Compound Exercise; they work harder.
Thus, the smaller muscle group get more than enough work in a Compound Exercise.
From reading about training over the years, I have noticed the Eastern Bloc countries getting mentioned in their successes with getting their athletes to move up weight classes.
Reading What?
It is hard to comment on the information you have read without reading it myself. Please post it.
With that said, the method for increasing muscle mass and for athletes to move up a weight class are the same for everyone regardless of where they live.
The Fundamentals Of Hypertrophy
The key is understand the principles of Hypertrophy. Based on the research of Dr Brad Schoenfeld these three mechanisms are necessary for optimal Hypertrophy.
1) Mechanical Tension: Increasing Limit Strength (1 Repetition Maximum Training). Employing heavy weights for low repetitions.
2) Metabolic Stress: This involves "The Pump/The Burn"; the dominate factor for Hypertrophy.
Moderate loads for 8 plus repetitions per set, with short reset periods between sets.
Muscle Contractions trap blood in the muscle creating a hormonal cascade that promotes muscle growth; "Accumulation of Metabolites (lactic acid > acidic environment > GH secretion), Dr Jeremy Loenneke.
3) Muscle Damage
a) Weekly progressive overload during a training cycle, with the final week of pushing muscles to failure or near failure.
b) Loaded Stretching: Performing full range exercises that place the muscles in a Loaded Stretch. Examples: Dumbbell Bench Press, Full Squats, etc.
c) Post Exercise Sets Loaded Stretches: After each set of an exercise, preforming a Loaded Stretch of around 30 seconds. Example: Sitting in the bottom of a Full Squat with Barbell on your back for 30 Seconds. A low load in a Full Squat works.
Full Body Training
Based on your information, performing a full body training session would work for you; training let's say, Monday, Wednesday and Friday.
One method that could be employed is employing different type of Strength Training for each day.
Example
1) Monday: Hypertrophy Full Body Training
2) Wednesday: Power Full Body Training
3) Friday: Limit Strength Full Body Training
Gaining Weight
The key to gaining weight is increasing your calorie intake.
Research by Drs Layne Norton and John Ivy, independent of each other, determined that increasing your caloric intake approximately 20% ensured a greater gain in muscle mass and minimal gains of body fat; providing a good training program is followed.
Summary
1) Compound Exercises provide the greatest "Bang for the buck." The smaller, weaker muscle are overloaded. That means is not necessary to train smaller muscle, unless you want to increase the size and/or strength of that particular muscle group.
2) Hypertrophy Training involves moderate loads with 8 plus repetition per set with short rest period between sets for "The Pump"/Metabolic Stress.
3) Optimal Hypertrophy Training involves increasing Limit Strength and producing some Muscle Damage.
4) Gaining Weight means increasing your caloric intake approximately 20%.
Kenny Croxdale