Depends on what faction your facing. Wehrmacht I'd recommend using Tactical Support doctrine as the Calliope can easily wipe pak walls and such. Infantry Company which has the Priest does well against OKW simply due to the short cool down so you can constantly barrage his buildings either forcing his Sturmpioneers to constantly repair and risk wiping them or lose his buildings. Remember to use Major recon to reduce scatter and decrew your priest while waiting for the barrage to cool down.
Scotts I would suggest if your infantry is lacking in veterancy or weapons as duel scotts are quite a force to reckon with if used well.
