I've stayed away from pidgeneers as the rules are less clear than a mortar, they cost a similar amount, and are both completely ineffective in my trials.
I'll test them as a nuisance, following game as a mage bunker.
I forget where I read it, but engineer in a handgunner detachment to a spearbus next to a volley gun is how I will be fielding MEs from now on!
Unless I can ever find a second half to my mechanical steed engineer model (damn you bit lots!!)