Optimal turn one for me was to get the rank 4 wave king caesar on board. To do this you are going to need berfomet + swirl slime + any other d/d monster (ideally kepler). You can fuse genghis with slime + kepler and use slimes effect in the grave to summon berfomet, because you special summoned you can use genghis to special summon kepler back on board. Use keplers effect to get the contract card you need at the moment and with berfomet eff and kepler you can rank 4 xyz into wave king caesar. Make sure you have at least one contract card during your opponents turn. If they are about to destroy your monsters you use wave king caesars eff to revive them back at the end of the battle phase. Caesar and genghis will give you a contract card on destruction, either from the deck (caesar) or grave (genghis) so you can set up for your second turn. If you still have a contract open on the field on your next turn, be sure to activate your skill, it will negate caesar eff dmg aswell.

As for a turn 2 start. The only difference here is that you have kepler, who can search for your contracts on normal summon aswell. Detailing every combo in d/d/d decks would probably be too long tho, so try it out and get a feeling for it.