Thyristor Trigger - PCB Design

I need a compact PCB that triggers an MFA90A thyristor from a relay while handling a 300 V DC line coming from a photovoltaic string. The board’s purpose is to short-circuit the PV panel and automatic re-triggering whenever both the control relay is set and PV voltage are present (also after night.

Key technical notes
• Input: PV string voltage ~300 V DC, so an on-board regulator must generate a stable low-voltage rail for the gate-drive circuitry and logic.
• Switching device: MFA90A (SCR-class thyristor). Diode in series with the string, thyristor shortcutting.
• Trigger source: dry-contact relay set by external signal
• Operation: if the relay is closed when voltage on the PV line appears (morning), the board must re-fire the thyristor..
• Robustness: components, PCB clearances and creepage distances must meet typical PV safety margins.

Deliverables
1. Schematic with part identifiers and values. I do have a schematic idea as well.
2. PCB layout (Gerber + pick-and-place files) respecting 300 V isolation rules.
3. Bill of materials
4. Brief design note explaining the regulator choice, pulse-shaping network, and any protection

I am happy to review early drafts and provide test feedback, then iterate once to finalise the design.