The amount of lights required to reach 99% tier-5 chests (you have around a 1% chance to get a tier-1 chest no matter what your lights are) varies depending on how many abyssites the person with the killing blow has. For instance, kismet abyssites increase "fortune" with blue chests, and having all 3 of these makes it so you only need half of the capped amount of azure (128) to see almost all tier-5 chests. In Heroes zones, the dominion status in the zone can increase this "fortune" further, making it so you need even less than 128.
In general, assuming you have all 3 kismets, there's usually no need to go over 128 azure unless azure is ALL you want.
You can get enhanced amber from ephemeral mobs which for the most part spawn every 5mins or so in each group of mobs.
Actually, enhanced amber comes from the roaming "avatar" mobs. Enhanced ruby comes from eph limules and amoebas; enhanced azure comes from eph clionids and murex. You can still get 16 ruby/azure/amber from any of these, but the possibility of 32, 64, or 128 only comes from the proper types.
Note that a few zones have some mobs that give double of certain lights (16 instead of 8). The treants in Konschtat and Attohwa are a couple of examples of double amber. Edited, May 3rd 2012 8:47pm by Fynlar