Hi Mark,
I use a PID temperature controller. There pretty easy to wire up and allows me to set any temp I want. Its nice for overlays and such cause it can be set for a lower temp then the bow was cured at. You can find them at the big auction site for around $20-30. I use one on a gas forge as well and works perfectly. If you decide to go that route and need help setting it up, let me know.
Dan