Early April is during spring break, however it's a Sunday, which traditionally for the parks, Sundays and Monday are the slower days. Also, I do not know what you mean by on "the later side", if it's well past traditional dinner time, it might be slower too. Unfortunately, I do not have a personal example myself of Toothsome, but traditionally my own advice for going to somewhere that is usually busy, or unpredictable: Get there before you're starving, or have a snack beforehand.
Also, if you have a smaller group, such as two, or three people you'll more than likely get a lower wait time, or at least whatever wait time they give you, it'll be shorter than predicted. That isn't a fact. However, my general experience with busy, or traditionally long wait restaurants is 9 out of 10 times that's the case.