Indeed, as Menachem commented, it's not necessary to assume that they were made into a dough. No kometz (handful) was taken from such menachos (see Rambam, Hil. Pesulei Hamukdashin 18:8), so it may not have mattered much whether it could hold together as a solid. (With private menachos, on the other hand, the ratio was 1/10 eifah flour (7.2 log) to 1 log oil, which would probably make for a pretty stiff dough.)
There is also the case where the kometz of a regular minchah gets mixed up with a minchas nesachim (Menachos 22a), where R. Yehudah points out that "they absorb [oil] from each other" - and Rashi there (ד"ה והן בולעות) notes that it's not really "each other," rather that the kometz will absorb oil from the minchas nesachim. This also suggests that the latter is more crumbly (or perhaps, as yitznewton said, batter-y), otherwise the oil wouldn't be wicked up out of it so easily.