You may have thought along these lines, but consider a Ouija (or via Tarot, or pendulum- which makes more sense if you have EA’s Divination vid course)… as symbols of Contact. Whether that Contact is with a Wandering Spirit, a Deceased Person, a Demon (whether historically known, a godform, angel, elemental-freq as a Watchtower, or from “outside” and beyond): these are all different Currents (just as diff types of People can be quite different)… but all can be contacted.
Thus whether Indirectly (via a symbol-system) or Directly (through direct knowing-connection), that can be done with a Sigil (with deceased the Name, perhaps picture of, Gravestone rubbing if, or if there is a newspaper article clipping.. just writing this bit and temp in room cooled), that can be via Scrying (in a bowl), autowriting, or actual Evocation. (evoke either a slight-sense of presence, or a more dsitinct Shadow- which will change the Enviro a bit, or all the way to Full Concrete presence... )
Whether sooner or later (after passing-event) would be better, would seem to change "who" you contact, but as much Necromancy is much later, and yet other Workings are done prior to enternment, so ...
I’d suggest part of beginning any of the above works, choose a method, and then the initial Contact (you want to get a response, connection) and interpret that (thus if you don’t get an immediate Download-of Knowing, then the Indirect,
ie a divination system like Tarot, or Dream-vision, or Ouija, whatever you use to interpret an Intuition sense if you were to unfold it to more specifics.. part of how you determine you will work (subj synth- prep immersion)