FWIW as a coffee person as well as a beer person, I'd consider somewhat emulating normal coffee practices. What that would mean is if you do it hot, do it around 200 F and for a couple minutes max. Maybe throw it in a little bit after flameout and just before you begin chilling? Otherwise during or after fermentation, follow the cold press steps. Consider something like 24 hours. Cold press is said to get rid of bitterness vs. hot, but IMO bitterness isn't an issue if you do hot correctly (i.e. not too hot or too long).
I aim to use coffee in a batch soon but never have so that's all with the "grain of salt". My plan is coarse grind hoping it'll fall out better, dark roast but not oily just in case those oils kill head, and added 24 hours or so before kegging. 1/4 pound sounds about right to definitely taste it but still have beer w/ coffee flavor and not start thinking it's coffee with beer flavor.