I just wanted to post back and follow up on my "sick" GL4. Not sick after all, but I guess my Pila LA's are.
I ordered and tried a Lumensfactory HO-9L 450 Lumens LA. Works great. It is brighter and whiter (on 2 x 600P) than my Pila 550 LA on 123's. Problem solved. The light is performing great now. I fully recommend the Lumensfactory LA's and plan to order more.
Many thanks to JSB for stepping up and offering to help with this.
-Bill