This seems like one of those things that’ll come up from time to time due to the typical skirmish game’s “Destroy/Cripple XX% of the opposing force” objective. Since the mission is the destruction of a force-in-being, rather than some other objective, you lose the option to just maneuver around the low mobility units and leave. In which case, otherwise trash units like Urbies become rather efficient; they HAVE to be dealt with, so they might as well spend their BV on armor and guns.
This is something I inadvertently took advantage of in a BV-matched 3025 campaign way back when. I collected a bunch of Urbies my teammates didn’t want into a very expendable Lance, thinking to use them up earning C-Bills for units I actually wanted. And then I had a surprising amount of success with them. At barely over 2k BV, match ups were often against bug-mechs that couldn’t out range them, and that a single lucky AC-10 shot could put on the ground.
Looking at your friend’s Lance, I’d be willing to rematch the death-ball with it, but I’d go in expecting a long, frustrating game. Given the option, I’d deploy on the mountainous map with my Mechs split 2-and-2 towards the map edges. I think I’d pair the Ymir and Gladiator, with the Firebee and Mongoose as the other element.
Overall game plan:
1. Move towards the midline between the maps as quickly as I could.
2. Watch for which pair the death-ball heads off to try and corner. Deny battle with that pair as long as practical.
3. Get my other pair onto the clear map as quickly as possible.
4. Plink the Demolisher, hoping to slow it down. Ignore the UM-R60 if either of the other targets are available.
5. If at all possible, never exchange fire at less than 7 hexes. Force the choice of spending ammo on 10+ to-hit shots or just having no answer.
6. Harass until one of us quits in frustration.
Reasoning behind the plan:
1. Demolisher is the primary target, since it’s the only unit with the ammo count to keep taking low hit chance shots. If slowed or immobilized in the open, it can be destroyed a leisure. The Urbies will run out quick firing on 9 or 10+.
2. I want to keep the Urbies out of the mountains, where their jump jets would be handy, and my fast units would be losing TMM.
3. I also want the Demolisher out of the mountains. I don’t want it finding an LOS hidey-hole that could force a “come and get me” situation.
That’s about the best I can come up with for playing the odds. But when dealing with AC-20’s, hot dice at the wrong time can always throw the plan out the window.