I've never used eco earth for snakes, but have when I used to deal with scorpions.

The two best options for humidity for me were: Cypress Mulch & CoCo Husk. I don't have a problem with Aspen, but when I get my White Lipped Python I want to keep the humidity in the 60's and during shedding I may elevate slightly, well my first go around I'm going to use CoCo Husk as I bought a few bricks to expand, then I'm going to let it fully dry out that way I can control the humidity and aim it the way I want. Cypress Mulch is great because it also helps with humidity and may be a better option for you.