I disagree with Koniving with respect to the builds, but his overall analysis of the entire Cataphract class is correct.
The Right Torso on pretty much most of the builds (outside of the 4X) is a ballistic and energy slot. The issue with that is you can disable more than half of the mech's entire firepower pretty easily since the mech has wide side torsos. The arms on the mech are also pretty low, which is a major hindrance...
The RT is ideal for an AC20, but you must balance that by making the left side of the mech equally viable... especially in the case of the 2X. You can certainly put a Gauss Rifle in that section, but that makes an XL engine not ideal.
XL engines are only ideal on the 3D, since you can somewhat minimize of the impact of being side cored with JJs. You don't have that luxury with the other variants (well, minus the 4X). If you wish to use an XL engine, then you will have to invest in long range weaponry like Large Lasers or PPCs.
The side torso weapon hardpoints are ideal to put in your strongest weapon due to higher weapon placement... but the low arms can make things difficult... so you'll have some problems with the SRMs you put there on the 2X (even though Streaks are homing, they'll probably hit the wall) so you want to be fighting on level ground to be most effective.
The 1X can be made a "mini-Stalker", due to the spread of the hardpoints, and you can invest with the XL engine if you wish as long as you aren't forced to brawl. A slower STD engine can suffice if you need the extra tonnage for DHS... It will still have poor convergence because of the arms, so you need to factor/plan this in advance.
That's all I have... the mech is not for newbies (the only heavy that is even reasonably newbie friendly is the Catapult... but then there's the huge cockpit...)
Edited by Deathlike, 07 July 2013 - 07:39 PM.