AVR prog for heater controller

I have a project that I need help on. It's an on-demand heater controller, hopefully using an Adafruit AVR Pro Trinket or Arduino Pro Mini 328 (or similar small/cheap) dev board. Project info: 1) Circuit/code is bare bones: needs to read a 2-wire 56Kohm thermistor (have temp chart for the thermistor), output controls a single SSR (3v-32v input), no display needed. 2) 12vdc available and will add small dc/dc reg to drop voltage to power the controller. 3) GPIO output to control SSR (if nec, could run GPIO signal through very small mechanical relay): output high at or below low-setpoint, output low at or above high-setpoint. (we will also want a reverse function toggle in code, for future use). 4) Need top level code variables for easy adjustments to settings, including high-set-point (default 95C), and low-set-point (default 93C). No external buttons or other controls, all adjustments will be in the code (once we get it dialed, it will stay that way indefinitely). 5) would like to flash via OTS programmer dongle. I've got Atmel Studio and an AVRISPmkII, but could easily pick up USB or something else if needed. 6) the device must retain last setting/code between power cycles, must boot quickly. 7) function: apply 3V (or 5V) power to controller, controller boots and begins temp control routine, power off controller (there are other analog circuits that control everything else, including fail-safe issues). WE DO HAVE A SMALL BUDGET TO GET THIS DONE. The dollar amount posted is not a max. Qualified individuals please apply. Thank you!