Ive ran a Battlewagon full of boys a couple of times and did pretty good with them.They usually draw a lot of attention.
I do Ard boy shootas with an eavy warboss..he has cybork/comb flamer/bosspole/attack squig.I run a nob with a
BC in the group too for challenges(hasn't happened yet though).
I do a rolla on the wagon with a couple of big shootas,no need for any more guns...also take a plank as it can be fun to use and quite the surprise
With your setup you can squeeze the Wagon in between your Demos as they roll forward,covering the av12 BW flanks,then jolt out and wreck some face when the opportunity arises.
The next time I try it I plan to go with the Mad Doc as my
HQ,use Ard Slugga boys and give the entire unit cybork just to REALLY be a pain in the ass
lol