Design for Analogue Temperature-Controller PCB

I want someone to design a complete, affordable analogue temperature-controller PCB for an 800-egg forced-air chicken incubator. Use my attached photographs of an old controller that was working good as a reference, but do not assume the original circuit is correct.

Requirements

* Temperature adjustment: 30-40°C * Accuracy target: ±0.1°C * Precision waterproof NTC thermistor on 1.5m lead * LM393 comparator-based control or similar * External 10-turn temperature-adjustment potentiometer for accurate adjustments * Two independent 600 W heating stages * Four 300 W air-heating elements in total * 220–240 V AC mains input on the PCB as per sample and 220v AC output for heaters and pilot light * Isolated 5 V PCB-mounted power supply * Two separate solid-state relay outputs * PCB size not more than 150x100mm * Adjustable or calculated hysteresis to minimise unnecessary on-off switching but rather a dimming effect * Independent overheating protection and heater disconnect to protect eggs from overheating * Fail-safe operation on sensor failure and power loss * Through-hole components wherever practical * Four PCB mounting holes * Fan independently powered, without fan control circuitry * Redesign PCB and its tracks to handle the new spec of 1200w. Please develop a complete electrical schematic, component list, and PCB layout suitable for prototype review. Keep the mains heater switching in a separate protected assembly where practical. • Give easy access to the multi-turn potentiometers for adjustment when putting it in enclosure Identify and correct electrical design errors, verify component ratings and switching thresholds, and flag all remaining safety tests. This project will be split into two parts: 1. Design, prototyping, testing, and delivering all necessary files (schematics, BOM, Gerber files, NC drill file) under the initial budget of $250 USD. 2. Ordering components, assembling two controllers, testing them post-assembly, and shipping everything to South Africa will be handled as a separate milestone with its own budget.