Well, as everyone knows, no plan survives contact with the enemy, so let's start thinking about what can go wrong, and he tells deal with it.
Best case, the enemy goes after local demi-spires and doesn't bother us the turn. If this happens we should be very happy, but it isn't otherwise worth considering.
Worst case they rush all their resources at one belt spire. This would probably be bad, no matter which they choose to rush. I will assume for disaster planning purposes that they did a ship and an infantry design, and both turned out ok. In this scenario we get our asses kicked on the one side, but are unopposed on the other. Classic good news/bad news... Not the end of the world, but we would need to make a special effort to reinforce the spire we have and focus on keeping them from securing the one we battled over. Hopefully in a case like this we at least manage a beachhead despite their attacks...
Second worst case would be if they try the same thing we are. Hopefully we are stronger, but I wouldn't count on it... If both sides contest a spire more or less evenly we will probably both end up with beachheads. In this case reinforcing is of utmost importance.
I really hope they rolled all 1s... That would make the early game so much easier.
Anyway, next turn we probably need to focus on more marines, finishing our new hull, and possibly some equipment revisions. Not sure what to revise, but I'm sure it will be clearer once the battle report is in...