Perma-PA is always the end goal of illusion controllers especially since it's their bread and butter for doing damage, tanking, AV fighting, etc. :D As a happy side effect, your goal to perma-PA will also involve perma-Accelerate Metabolism and perma-Hasten.
I normally skip Choking Cloud and Fallout as they don't fit my playstyle on my ill/rad.
I normally don't bother with softcapping on my ill/rad as the Phantom Army will be the ones tanking for me, with Phantasm as the backup (very backup, his goal is to basically use his decoy which is immune to damage to tank for me in the event for some reason I can't summon PA in time).
If you can achieve perma-PA before incarnate alpha, then musculature radial paragon is a good way to go, as it will add damage to your ST hold, along with your attacks and pets, and give you more -tohit and -def on RI toggle.
I took Psionic Mastery on my ill/rad to give me Psi Tornado (which has the force feedback proc) along with a mez protection clicky.
Here's my build if you want to get some ideas. If you don't like Arcane Bolt, you can always shuffle powers and replace with Mental Blast if you choose to pick Psionic Mastery.
25th_Pirea_2019_-_Controller_Illusion_Control.mxd