No DFG - Maxing CDR on AP Assassins

Since Riot announced they are removing DFG in 5.2, I am going to be missing out on that 10% CDR that DFG gives me on the AP assassins that I play (LeBlanc and Syndra).

Currently I use the 5% CDR masteries, 6 CDR glyphs (5% CDR), DFG, and Morello's/Athene's for the max CDR build.

Without DFG in 5.2, I have a 10% CDR void that I need to fill. I am thinking of using 9 scaling CDR glyphs so I get 15% CDR at level 18, which allows me to retain max CDR without going over the limit or anything.

However, this means I miss out on Magic Resist glyphs which does make me consequently more squishy and easier to kill.

Thoughts?

EDIT: Twin Shadows is a more gold-efficient alternative if I want that 10% CDR. I will miss the 120 AP from DFG though. ;-;