You might want to consider putting some homasote, or similar sound insulation between the track and the plywood. Screwing the track directly to the plywood, especially with a lot of screws, will be extremely noisy. I couldn’t get homasote where I live so I used 2x4 ceiling tiles. I only use a few screws at key points such as curves and couple along straight sections. I use 1 1/2” #4 screws. Get Phillips or Robertson (square), they are much easier to drive than a slotted screw. You won’t find these in the big box stores, so use the references Carl gave you. I also leave the screws a little loose so there is about 1/16” vertical play in the track. If you tighten them it just transmits the noise to the plywood.
