Packing mass for heavyweights

If a fighter wanted to move up from cruiser to heavy and was looking at adding another lets say 2stone to his frame what would be the best way to do that.
We see a lot of fighters who have put on a lot of weight to get themselves to what they are weighing now az heavyweights, Anthony Joshua is one of them.
Hes obviously added muscle mass to his frame to increase his weight but im sure you have to know the best and worst places to adx the mass.
For instance im assuming adding mass to youre arms is undesirable, massive weighty biceps and triceps would be more of an hindrance im assuming.
I would of thought glutes and back thickness is the best way to go, where performance would be inhibited the least.
Whats the best and worst areas to pack to mass on for the fighters that are trying to make the jump to heavy.

 

Thanks for replying.
I know how to put muscle on through diet and rep and set range but im guessing that theres better places to add the muscle than others.
Im asking which muscles and muscle groups are favoured over others.
I would of thought adding 2lbs to your glutes is better than putting 2lb on your arms for the obvious reason that your arms are punching and will tire quicker.
Which areas are favoured over others.
I know that you dont want to be adding too much (if any) mass to your calves as this can gave a worser effect on your performance

 

Ok so lets assume that ive nailed my diet and i am starting a weightlifting programme.
Dont you think that there would be certain bodyparts that should be prioritised before others, certain bodyparts that would be more detremental if i added mass to them ovet other bodyparts.
Would a programme aimed at all over muscle been added, giving each body part equal cosideration be the best.
Or prioritising certain bodyparts such as back depth and traps, glutes, quads and hams.
And not doing any specific work on things like arms, calves. Would that be the best..
Im thinking that adding too much muscle to areas like the arms would be more detremental than if i didnt add muscle to the arms and then instead of adding the 1 or 2 lbs that i would add to the arms in an allover programme(giving each bodyoart equal consideration) add that 1 or 2 lbs as extra muscle to the glutes or back..

In boxing certain muscles get used more than others.
In javelin one arm and shoulder (the one used for the throw)develops more than the rest of the musckes in the body. Them particular muscles are more sport spefic and get used more, so they develop more and increase mass in those areas because them particular muscles are been used more.
The same in boxing we are relying on specific muscles and muscle groups more than others, these muscles are specific to the sport.
Would it not be better if one wanted to jump up a stone or two to heavyweight to add muscle mass specificaly to the muscles and muscle groups that are less sport specific in boxing?
If so...then what are these muscles and muscle groups.
Or is it just better to add the muscle mass on all over.

 

So your saying that if you want to jump up to heavy and i need to add a stone or two as weight, then as a boxer you should pretty much never build muscle.
So i would need to add the weight as fat?