Spit VB never had more than 60rpg in its wings for the 20mm.
The Spit VB had Hispano Mk.IIs as well, not MK.Is.
The Spit VB wing remained unchanged in its service life, the blisters it had are evidence of the 20mm cannon mounting the drum. To have a VB with belt fed guns means altering the wing, they never did that.
The Spit VC with the Universal Wing, had belt fed Hispano Mk.IIs with 120 rpg in either 2, or 4 mounts.
The confusion goes like this: The Spitfire VC had the 120 rpg for its cannons, but most Spit VCs has the so called "B wing armament" of 2 x 20mm and 4 303s. That gets bastardized by folks into this: The later Spit VBs had 120 rpg". Close but not correct.
It also does not help historians that Spit VBs and VCs are externally, in many cases, almost impossible to differentiate. There have been many errouneously produced pics and docs because of this.
As for the Hispano Mk.I that never was used in the Spit V, that cannon was the original British design from the French plans, installed into the Spitfire IB. They were a failure due to design problems converting metric to imperial. The improved Hispano II served in all subsequent wartime Spits.
The Spit VC was the definitive Spit V model, it had a stronger fuselage, more ammo for its guns, a bomb rack and a 4 cannon option. It served in the ETO, MED, SW PACIFIC and CBI.