Yea, Balbo, though a "wunderkind" and one of the "Ras" of the Quadrumvirs at this stage, is not a likely candidate yet.
Of course wait 'till the mid thirties, however...
(possible upcoming TL of mine on just this!

).
LordKalvan's likely on the money with Farinacci, which bodes
really scary as he was very much pro-Nazi. Likely Italy supports the Reich from the beginning. Antisemitism policy starts much earlier. Perhaps even deportation of Italian Jews to the Reich's camps!

Of course OTL he was implicated in allowing the Matteotti murderers to go free, so maybe he's going down with Il Duce.
Other options include De Bono, though since he was implicated in the Matteotti murder OTL he's likely going down with Il Duce ITTL too.
Bianchi is an interesting option since he's the "far left" syndicalist of the Quadrumvirs. OTL he dies of Tuberculosis in 1930, but that could be butterflied ITTL.
De Vecchi is a (by Fascist standards) middle-of-the-road option and a possible compromise candidate.