I've used this one with great success, multiple hatches over the course of several years (including setting it up for friends as well).I read a little more into this method, Like you most people have used them in pretty low temps with great success. May I ask what brand of heat pad you’ve had luck with?
https://smile.amazon.com/gp/product/B07V1GZGR4/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1
Chicks are resilient and can handle temperatures much lower than the common recommendations (those come from large scale commercial hatcheries and work for their setups, but aren't set in stone as a rule). Chicks hatched by a broody are out and about even in cold weather, as long as they have shelter and can go under her whenever they need to.