OP here reporting back after doing my home gym calithenics chest day.

completed:
4 sets of 10 +20kg weighted dips at 80 kg bodyweight (perfect form deep stretch below 90 degrees)
3 sets of 16 steep decline pushups
3 sets of 8 side ways push ups as decribed above.

The side ways push ups where quite intense, providing a deep stretch at the bottom for the working arm/chest, and a massive squeeze/activation for the upper chest at the top of the movement. I am actually able to feel a pump in my upper chest, seems like I actually targeted it for the first time, even as I am typing this I feel my upper chest.

The movement did not feel awkward at all, and set up was easy with a stack of books elevating the working arm.