Expandable Control Panel Advice

I posted this idea on another thread but figure it may get more input if I start a new one. I appreciate the helpfulness of everyone on this forum and am always inspired by the amount of time everyone spends helping each other out.

I am planning an electric brewery build. Initially I will use my current 15 gallon HLT, 20 gal MT, and 15 gal BK to produce 10 gallon batches. Over time I plan to replace everything to put together a 1-BBL to 1.5-BBL brewery. I am hoping I can build a control panel now that will work for both setups. Here’s my plan/idea:

BCS-460 controlled 50a control panel operating one element in the HLT OR 1 element in the BK and two pumps. Generally the same as the EBrewsupply.com 50a BCS kit.

I would also like to incorporate two more elements (one in HLT and one in BK) to be controlled manually with a three way switch (HLT/OFF/BK).
The idea is that the system could function with just the automatically controlled elements but the manually controlled elements could be added for the 1 BBL system to decrease the heating time with the extra volume.

I know P-J has put together a ton of wiring diagrams but I haven’t come across anything like this. Does anyone have one?

Thanks in advance for any advice,
Kevin

If your future plans are to increase to 1-1/2 bbl. then consider building at least a 60A capacity panel. I am using two panel boxes so everything isn't crammed in and it allows for easier expansion. Just a thought!

Bueller...