Well, there are a few spreads.
The first one is the standard bulky Smogon spread, but personally I dont like that.
There is also:
110 HP / 216 Atk / 184 Spe Adamant
148 HP / 176 Atk / 184 Spe Adamant
188 HP / 136 Atk / 184 Spe Adamant
These spreads all allow for the outrunning of Max Base 115s which is mostly concerning Starmie. Starmie is very important to outrun, as even if it is the Smogon "Spinner Starmie" and it switches in whilst you Dragon Dance, you can finish it off when it is below 70ish%. The Atk is just the three highest jump points (as I am sure you know) and HP filler.
You can also consider Kingdroms Gyarados, but imo that is too bulky. Im not too sure whether your team had a status absorber but a ResTalk Gyarados could work. If you want a more offensive spread than 252 HP / 252 Def, VM me again.
If you were going to make your own spread aim for 184 Spe Adamant. But do not aim for optimal lefties, as this ties in with Stealth Rock meaning you lose extra health every switch in. And with the prevalence of sand storm, which is on around 30% of all teams, it isnt such a good idea as it negates leftovers.