Hi, my 4 month old is sleeping in a safe sleeping bag and is about to be moved into his cot next to my bed. Do I still place him with his feet at the base of the cot or can he be in the middle so we can look at each other?

It is mostly important to put the feet at the foot of the cot when the baby is not moving & you are using blankets.
This reduces the risk of baby getting head & face covered if they wriggle down under the blankets.
https://rednose.org.au/article/sleep-baby-with-head-and-face-uncovered

Once baby is in a sleeping bag & is moving around, blankets are generally not necessary, so baby can be placed in the middle of the cot.
Is your son rolling yet?