Avoid buying a 6-Link before Empower
Ideally you should buy Empower when CF is lvl 19 so you would have lvl2 Empower when CF reach 20
Then you buy a 6-Link and put them together to make CF cost around 2k life
Also you should temporarily remove Tireless cluster from the tree
(If you buy 6-Link before having lvl 24 CF (20+lvl2 Empower+3 from gear) CF would cost 1k life which is not enough to proc Adrenaline
If you add lifetap to solve this - Reap would cost a lot)
Make sure to put x6 CF in off hand to get lvl 21 asap
If you can't afford Empower - check out if you can buy
Corrupted Tabula with +2 duration gems It would work the same way as a lvl 3 empower
The 6th gem you put into it in this case is Controlled Destruction
(only works for Reap)
When you put Reap and CF in 6-link - you will have 4 sockets to spare so add Call to Arms / Enduring Cry