I think you're only getting conflicting sizes because of their personal preferences for how tight/baggy they wear their sweaters.

Personally, I think slim fit on sweaters is better as long as you're not going TOO tight.

Another option is Charles Tyrwhitt's wool v-necks. It is on the thinner side, but I personally think it is substantial enough. By comparison the wool-cotton LEC v-neck is very thick. Also, note that the LEC v-neck looks very casual and the navy is their usual odd faded navy (which I personally do not find very attractive. YMMV.)