What type of spring increases the force of the upstroke?

Title, complete noob to modding switches. I really don't understand what different spring types do and the lingo makes it difficult for me to even search around. Specifically, I really like the downstroke on the Alpacas but feel that their return is very weak. Typing experience feels kind of "floaty" when I'd much rather them feel like "BAM!", right back to the top -- might be exaggerating a little for effect, but essentially I'd just like to improve the return force of my switch. Thank you!