SDD fills us quickly.
We were at HS twice at RD.
Day 1 rode MMRR twice, walk on. By the time we got off, SDD was 60 minutes.
Day 2, rode MMRR at RD. Rode SDD, 35 minutes. BY the time we got off, it was 70 minutes, line outside of Toy Story land. An hour later, the line was only to Woody.
Knowing this, I would ride MMRR once at RD, do Toy Story Mania, then get in line for SDD as the line for SDD builds quickly, then decreases for a time, then grows at official opening and stays.