I dunno if you want specialized EVs and such, but here are the EVs and Natures I would suggest:
252 SpA / 252 Spe / 4 Def
Tropius has some pretty horrid defences and defensive typing, so you want to hit as fast and as hard as possible. Honestly, if you want a Harvest staller, Trevenant is better than Tropius both offensively and defensively, but hey, whatever floats your boat.
248 HP / 252 Atk / 8 SDef
Bulky Primal Groudon is bulky. He is meant to tank all of the things, then Precipice Blade all of the things. Adamant nature ensures maximum carnage.
His moveset also pains me. I'd like to make a few suggestions. First off, replace E-Quake with Precipice Blades. Despite its dodgy accuracy, Precipice Blades has superior power – which is important when factoring the 25% power drop of spread moves – and it won't hit your (non-flying) partner. Second, Protect should be used over Brick Break to avoid unwanted Earthquakes from the likes of Landorus and co. while Tropius Solar Beams them.
I hope this helps you break all the things!