I'm a rank 1000+ 4v4 player so take what I say with a grain of salt
Using engineers in place of your conscripts is a pretty bad idea unless you're going to be giving them SVTs.
The reason is that they perform pretty much as if they were a 4 man conscript squad, so just theoretically, if you took 4 engineers in place of 4 conscripts, your army is short 8 men at all times; short 12 men by the endgame, even.
If you want to keep using engineers against ass grens, you're really going to want to bring more MGs and use your ability to deny the enemy access to cover w/ barbed wire as often as possible. Planting tripwire mines will take models off ass grens at least until their squad leader upgrade (it may or may not kill a model after it, I forget).
Usually with conscripts the play is to use cover advantage and either retreat outright at close-mid range or soft retreat to an MG around mid range.
The biggest weakness of assault grens is lack of snare (which unfortunately you're also suffering from), so try to bully them with a T70 or AA halftrack.