I don't know anything about solo play, but if Mech Attack works for solo play for you, then Alpha Strike should also. We've used both systems to good effect. The difference being that Mech Attack works well for 5-10 units per side but slows considerably after that. For Alpha Strike, on the other hand, 10 units is probably the minimum per side that one would field as the streamlined mechanics require more units for an engaging game.