Hi my friend, i will be honest, i don't use reaper, i use pro tools or fl studio to process al my recorded sounds..
I make the most part of my sound fx recording directly with my mic in the ambient... Footsteps per example, i put my mic, some shoes, different materials, record any of these sounds, and process, equ, mix, maximizing, with these DAW..
I don't know if works for u, but if you like i can show u some of my work, i've made sounds and music for games, and films..
Greetings.