3 - Weekly Attempts
This is the one I had the hardest time thinking of a solution to cover. This is where you can get the OMG awesome gear that is comparable to gear you would get from Coil.

The way I envision this is having a progressive crafting challenge similar to progressive difficulty in passing Coil waves.

RULES
1) You can only attempt a craft for this once every 90 minutes.

2) If you complete a craft successfully, an item will drop. If the item is for your highest iLvl combat class, you will have a 75% chance of acquiring it on roll. If it is for any other class, you only have a 10% chance. (reflecting the odds of getting the drop and subsequent roll on a piece of loot in Coil)