Midas' numbers have been very stable for nearly 2 weeks. He's not gone above 351 and isn't hitting the high numbers he once was but he's not gone under 200 either.
Yes, he does need to go to 8U. You don't need to hold a dose where you don't see blue or green nadirs for more than 3 days.
Considering that he has seen green at lower doses, you can increase every 3-4 days till you start seeing green nadirs.