welcome Murray! I would never have guessed you would do armor. just so you know what's what, I'll give you a rundown on the sherman's variants (I won't go into their different versions though)
An M4 sherman tank(early versions had 75mm guns, later vers. had 76mm guns)
A sherman firefly (the british version of the sherman)(17 pounder gun)
The M10 (a tank destroyer made with the m4's chassis)(76.2 mm gun on it)
The achilles tank destroyer (the brit version of the m10)(it had a 17 pounder gun on it)
The M32 recovery vehicle which was based on the M4
an m36 tank destroyer (based on the m4 chassis)(had a 90mm gun)
The M7 priest was a self propelled artillery piece using a 105mm gun(later versions used M4 parts)
the sherman calliope (rocket launcher on top of the turret)
The BARV (Beach Armored Recovery Vehicle) (It was to provide vehicle recovery during amphibious invasions)
The Duplex Drive Sherman was an ordinary sherman had a flotation screen around it for amphibious landings and it had to propellers for power in the water.