1
is much, much too low for such an ability, in my opinion.
Consider:
1) Cloak essentially grants immaterial/enchanted to all creatures and permanents (with minor vulnerability like Plague). With 4 creatures and 4 unique permanent stacks (a conservative guess at 'average'), it would cost 24 quanta spread across two elements (without Annubis), or 24 quanta spread across three elements (with Annubis as a fifth creature) to accomplish the same feat. (all numbers from unupgraded)
2) 6 Cloaks cost exactly 4 x 6 = 24 quanta. That gives 18 turns of protection. 24 quanta with Ink provides 24 turns of protection.
3) Cloak can be destroyed and stolen. This ability cannot be disrupted. (did not read properly)
4) 1 Plague takes away 3 turns of protection. 1 Plague takes away 1 turn of Ink.