hello! i'm planning on getting a snake soon, and i'm wondering if anyone has any experience with DHPs?
i will be using a 40gal glass tank, which i have heard doesn't retain heat very well, but i will be insulating the sides
i also plan on using a thick layer of substrate, so i don't know if a heat mat would be ideal for that setup

anyway, my questions:

would a RHP act as a good sole source of heat or should it be paired with another heat source or a second DHP?
can putting slate or something similar under the DHP can help radiate the heat throughout the enclosure and will this help ambient temperatures? my house is generally on the colder side, around 65-70F/18-22C
does it create a good temperature gradient and about how far does the heat reach on the hot spot?

i understand these are pretty base level questions, i'm a beginner at this, just trying to get everyone's opinion

any other information you can give me would be great ideally i'd go for a pvc cage but i don't have the money for that, so i'm just trying to provide the best life for my first snake on the budget i have

on a side note.. does anyone use and like VE thermostats? i've heard good things about them

thanks!