I always found myself using Professor Elm's Lecture for initial set up, esspecially now that Nest Ball and Ultra Ball are rotating making individual search for pokemon during turn 1 not nearly as reliable as the current format, even though we don't have Tapu Lele-GX to search out Elm's anymore. I still think it's going to be an excellent card for post-rotation though, for a couple reasons. Firstly, Elm's puts the pokemon into your hand, not the bench. This is important when you need to search for pokemon via Pokemon Communication, so you can use Elm's, search for 3 pokemon, bench 2 of them, and then Pokemon Communication the third one to search for draw power such as Dedenne-GX to get draw power right afterwards. And speaking of Dedenne-GX, that's reason number 2. Getting a fresh new hand and setting up your bench on the same turn I think is very good. This goes so well with Cherish Ball (Item Card; Search your deck for a Pokemon-GX and put it into your hand, shuffle your deck afterwards.), as it not only searches for your Dedenne-GX when you need it, but it can search out other Pokemon-GX that evolve from the Pokemon you put into play. Specifically in stage 2 decks, you can bench Alolan Vulpix with one of Elm's searches, then have Cherish Ball in your hand to evolve into LOT Alolan Ninetales-GX to search out Rare Candy and another Cherish Ball to search out stage 2 GX's like Dragonite-GX (the new one). Here's what I like playing around with numbers-wise:
-4 Professor Elm's Lecture
-4 Pokegear 3.0 (To open with it as often as possible)
-4 Cherish Ball (4 of them is not overkill, as it unbricks you with Dedenne-GX in your deck and searches out other key Pokemon)
-2, maybe 3 even, Dedenne-GX (For draw power)
I'm currently working on a post-rotation Dragonite-GX deck, and so far it has this engine in it. So far in my playtesting, leading Dedenne-GX kind of sucks but it's still possible to get crazy setup like this. I'm gonna keep trying this and see what else I can do in my list.