So the way CV works with the absorbers specialization is better. The way the actual formula works is it raises all six aspects to the power of four, sums them, gives an efficiency bonus of 15% for every aspect over 4 after the first one, then accounts for the efficiency of the generator before dividing by 25000? That last bit might be 2500 actually but I don't think so. Anyway that means focusing on just one aspect is better, scaling with the fourth power does that. So a node with 35CV of each vis that'd make it 441 EU/t in a HV absorber, alternatively for a 210 CV node that was 5 of 5 of them and 185 of the other it'd make about 49k EU/t in an EV absorber, by those numbers the minimum total amount of vis to max an EV absorber is 97 CV of a single type. Assuming all the aspects were equal you'd need 54CV of each aspect. Note though I'm pretty sure it can drain from multiple nodes at once, so three nodes with 18CV of each aspect is just as good as one node with 54CV of each aspect.
As for essentia or enchants, it'd really depend on what way you make them, you'd be right that you'd be hard pressed to supply them fast enough. Essentia the best bet would be an automated tempestas setup most likely, each point of that should generate 6400EU if I'm reading this right which would make it need about 6/second. A tough amount but that should be doable with a decent amount of effort, for 2048EU/t it could be worth it if you're not abusing bees or anything. Enchantments are more complex, but a test with 10 buckets of liquid xp and the openblocks auto-enchanter set to level 1 gave about 30 enchanted tools (dark steel was used for maximum enchantability) which totalled to 960k EU, so about 96 EU/mB which is actually a pretty good output for a fuel, you'd need a good mob farm to keep though, at least the auto-enchanter seems to enchant at a blazingly fast speed. If you figured out how to do something like automate the dragon essence altar you could improve it further as that can upgrade enchants, can't automate getting dragon essence though which could make things tricky. A good enough method of automating enchanting items could work though, maybe you could do something with thaumcraft?
@Bob558 did you make sure to put it in a UV light box first? Otherwise you can't etch it.