installing aux water temp gauge-where to put sender?

Installing a a pillar water and trans temp gauges, where is the correct place to put the sender unit? I can use the coolant temp sensor hole on the side of the block, its no longer needed, or can I use the new sender in the original sender hole in the head and run both the dash gauge and the aux gauge of the autometer sender?

I put the sender for my Autometer gauge in the original location.
Or you could use late model thermostat housing and put it there for temps at both ends of head.....

I did the same thing. Used the later model waterneck on my Renix block.

I have a RENIX so I put my CTS in that spot.