I can't recall if I made them though MS or had to call the restaurants myself--almost think I had to call the restaurants direct.
Remember, Wednesday is members night at Sonya's you get 10% off the bill.
I will add that the menus seemed very limited. Not even sure anything but the snack bar at the pool was open for lunch, and maybe the green cabin room bar.
In all honesty, we had breakfast in the villa each morning, except Sunday we went to brunch at Sonya's. It was good, not fantastic. Dinner there was also good, not fantastic.
We had purchased lunch meat and snacks as well at the grocery store in town, and had lunch at the villa each day. We sometimes would grab fries from the pool snack bar to go with the sandwiches for a treat.
I never ate at the other restaurant. The night we arrived I was quite ill, and just went to bed. DS and DH ate there, and complained the menu was not very appealing or broad.
We grabbed a light dinner at the Green Cabin Room one night, pizza or club sandwiches I think.
The other nights we went into town to eat. The Ocean Grill was definitely the best, very good) but a tad pricey. We also ate at an Italian place that was pretty good, and at one other restaurant that was good, but unremarkable.
Back to your original questions, I want to think it was 30 days out for making PS ressies. We didn't make reservations at any other places until that day, and never had a problem getting in. It seemst aht Sonyas will be the harder place to get in to, it appeals to a lot of the locals as well, especially for Sunday brunch.
Best bet is to call MS and ask them.
Have fun!
Anne