Reducing the range too much would be a bad idee...if this applies just make them(LefH and ML) movable or something,with very slow speed,and slow packing/unpacking time...like this you can evade bombing but have to leave your base to fire,leaving them more vulnerable to ground units
Skipping T1 means he doesn't have any anti-tank...when you see this strategy I would recommend building T1 and two M3's,after that upgrade your engineers with flamethrowers and place them in the M3's...then enjoy his doom buhahaha
Oh and don't place the scout cars in front of the machine-guns,they are quite squishy