To be honest, I think that at the recovery rates most folks are experiencing (1-3lb/minute) anything over a single 1/2” recovery line is overkill.
You could calculate choked flow for a given mass flow and see the cross sectional area at which the flow is choked—but I doubt it’s gonna have a major effect.
As most will mention here, heating and cooling are far more important. Also important to note that the smaller the bore size (typically) the higher the pressure rating.