Direct translation of one of my older Grasshopper builds onto the Warhammer chassis. In fact, the WHM itself seems to be a less vomit-y, less jump-jety, more supportly-long-range-y type of mech, especially with the PPC quirks. The lack of high mounted slots and adequate space for extra DHS and XL makes it a little less desirable than the Grasshopper as an energy brawler.
I ran mine with 4x LPL and XL325. All LPL in the Side Torsos. The arms are just too low mounted. Min/Max, IMO, would be all ST mounted. Felt just like a mini BLR or BNC. Fits the tonnage and slots very well with 19 DHS. You can't run a ST based build on the 7S as well because of crit slot issues in the side torsos. You could technically move a DHS from the RT to the arm and then have 2x LPL in each ST for a good 7S build. I will probably end up doing just that. Performed very well on HPG and Polar. The high mounts means this is the lightest mech in the game atm that can viably run 4x LPL. Grasshopper isn't as high-mounted and the geometry is better on the Warhammer IMO.
Running something similar, just like having near Max Armor. Also like having 2 on each side so I can group them by Left/Right to make firing around obstacles a little easier.