You are definitely on the right track. One tip that may help is using AlignPlanesMFD to determine launch time. Select ISS as the target, and watch the TN. Keep in mind that Sync is assuming both you and the target are in orbit. Since you are landed, the TN (Time to Node) displayed will NOT be accurate, but it's still fairly consistent in it's "error". In other words, just because TN displayed is, say, 300 seconds doesn't mean you will reach the node in 300 seconds (it will actually take a bit longer). However, as I said, it's consistent. Therefore TN can still be used as a reference. I find that launching when TN = 300 provides quite good results (less than 1/2 degree RInc) with the stock DG (about 360 for Atlantis). Launching into an orbit with very low RInc is the single most crucial element to getting a good score on this challenge. From the score you posted, you are already doing pretty good at this!
I can promise you that there are more than a few people here who consider themselves "advanced Orbinauts" that couldn't score as well as you did.