The "E2" that I think they are talking about (the reference was on an Eagle Cals Decal Sheet,with a TINY picture showing no detail, EC#11) is one found mostly on the Doras, but it's not the cigar one, but a teardrop type with a metal 'lip'horizontally around the middle. Unfortunately I can't get a pic to post on here (hence my question),but it definitely doesn't look like the 'standard'common 300l luftwaffe tank. It seems to resemble very closely the USAAF 75Gal drop tank..?
I have found a reference that i think may be the 'E2'tank, in Squadron's 'Bf109 In Action', on p20, describing a similar but not identical tank as a 'type B, rarely used', but I really can't be sure?
PS: the 'common' luftwaffe tanks are described on the same page as Type C and Type D, they are recognisable by their vertical weld lines and small breather tube on the front.