Difference between base values and buffs
Wondering if full set of chameleon stacks? Wanting to understand more about sneak? This article holds the answers.
Be advised that sneak mechanic has been subject to balance changes that were not communicated in patch notes - multiple times. High probability is that some of these changes were unintended, as one description of these changes could be "there was a period where everybody achieved max sneak easy". Since its a rather complicated mechanics to research without access to console, some of those changes go largely uncommented. The point of the article is to present the foundations of variables we have at hand, and how they interact. The exact results of those interactions are subject to changes by Bethesda, so in advance I apologize if it becomes obsoleted.
Sneak is a measure on how good your character is at remaining undetected by opponents. Your total sneak is put against opponents perception check to determine the state of their awareness. The things you do have a negative effect on your sneak. You can reduce how negatively you are impaired by your actions.
When you walk, you get a sneak debuff. When you walk slowly, or walk in gear thats modified to reduce detection, this debuff is smaller. When you shoot, you get a debuff, when you shoot a silenced weapon, this debuff is smaller. The more illuminated your character is by the nearby lightning, the higher the debuff.
There are few sources of sneak buffs. These are: chameleon mutation, chameleon armor, escape artist perk and aid consumables are temporary bonuses that can be triggered, The sneaking armor mods, both craftable and legendary, sneak perk cards and your agility - they all influence your base sneak, which is how much do you have while moving (or more precisely, when you're not benefitting from triggered sneak buffs).
To answer the question: will 5 pieces of chameleon armor stack? Yes, they will.
Is this a good setup for sneaker? When it comes to optimization, it's rather terrible.
If your goal is to maximise your sneak, and you do that by spending all your armor prefixes for this purpose, not only you'll get a second-class sneaker, but also an overall weaker fighter. The reason for that is that it's more beneficial for your sneaking to concentrate on your base sneak value (Sneak perk, Harder to detect while sneaking armor), you'll simply get sneakier than you'd be in chameleon set. Focusing on Chameleon is focusing on hiding after being spotted - instead, I suggest focusing on not being spotted at all. If you don't spend all the prefixes for chameleon, the character you'll create will be much less fragile in case you've been spotted.
For those of you wondering how does Chameleon Mutation compare with the Armor, the effects of the mutation for your sneak parameter between the mutation and the chameleon set are the same, but you're "visually more invisible" in weightless set than in single chameleon armor piece, and your 'invisibility' is greater with each next chameleon. This has impact mostly on PvP, where you need the prefixes for protection not to be one-shot. The drawback of being able to stand still, without crouching, and being invisible from the mutation, is that as soon as you fire the mutation deactivates and doesn't trigger up until you give it a short while.