Welcome! Interesting handlebar setup - nice to see yet another homemade/custom setup.
Saddle comfort (and handlebar) is a very personal thing. In my opinion you just have to keep trying to experiment with your setup until you find the most optimal setup.
A few random notes. The M40 Handle Saddle “S” is really short. I don’t think that is a good option. Even the M will very likely feel a bit short compared to your current setup.
You forgot option 4. 
(and probably a few more). What about a flat saddle like the KH Fusion One with a reinforcement plate and a custom handlebar?
Also why a mechanical brake setup. Even an entry level (40€?) hydraulic disc brake will likely give increased feel and power.
You might find some inspiration here for custom handle saddle setups.