That's not really an issue. Machine guns are light. A pair of machine guns and the ammo to run them weighs a single ton if you're using Clan tech, a ton and a half if you're using Inner Sphere. I'll bet Ben's got his Warhammer tricked out with captured Clan weapons (battefield scavenging is a proud BattleTech tradition).
If he's got an XL engine and Clan weapons, he can have that weapon load and max armor with 18 (double) heat sinks and a 4/6 movement. If he's using IS weapons it's still doable, but you start having to make design comprimises.

>
>I'd provide an example of the sort of philosophy I'd favor, but
>without knowing how Virtual MechWar's construction system
>works, I could barely even guess. ^_^

I would imagine it works something like this.

Polychrome

Old school BattleTech player.