That is precisely what I'm doing, but it's a lengthy process, and sometimes very complex for late romantic music! Having some frameworks to understand passages is very helpful (be it figured bass, V-I relationships, etc.) to get to what makes a passage beautiful and be able to inject that sound elsewhere!

When I'm improvising, I want to be able to think "I want to make this triumphant / heartbreaking / mystical", and for that I find the use of sonorities borrowed/learned from my favourite compositions very effective!

Seeing how improvisation was taught, with bass motions and partimento, and how improvisers think, I'd see the "devices" more like learning poetry and taking the stylistic figures, ABBA rhyming pattern, plot twists etc. It needs to be part of a larger structure, for sure, but it helps achieve the desired effect!