Photocell accessory for low voltage lighting

[vegget]

Which photocell to use w/low voltage system

I have a Malibu ML300 transformer/timer for outdoor lighting. I want to add a photocell to help with seasonal changes. There is a discontinued photocell for it as an accessory but, as it’s discontinued, I can’t get one.

Details: Brand: Internmatic Model: Malibu ML300 Output Watts: 300 Output Voltage: 12

I can’t seem to find one that I know would work. But, I don’t have the knowledge of what could/should work. I want to know the technical details as I know these don’t seem to last so I want to know what to replace it with if/when it dies

Can I use a 120V-rated external photocell instead for it? There seem to be a lot of those about, But, I don’t want to wire one of these b/f the timer as then I lose access to the timer part of the transformer. There is a C wire connection on the transformer along with the A and B wire connections that is meant for just such applications of adding the photo control.