I've been deworming every three months -- ivermectin in rotation with moxidectin, but have recently changed to a every two month, more vareity program (new barn, new vet). It is probably similar to what Solaris does.
It uses pyrantal twice a year, ivermectin or moxi in the spring, ivermecting or moxi PLUS praziq in the fall, and fenbendazole or oxibendazole thrown in there somewhere.
OK, here's a link to the chart. Only thing is that it's made by Intervet, who makes Pancur (fenbendazole), so of course it's going to tell you to use it, when you can use oxibendazole (Anthelcide EQ) instead. AND, it recomends doing the pancur-power pack yearly in the winter. I really wouldn't use the powerpac except on the advice of a vet. Personally, I'd just give another dose of either the oxibendazole or the fenbendazole.
I've seen many deworming charts, and I like this one because it doesn't just tell you "ivermectin in March," but has you check for weather conditions -- ie, freeze, thaw, etc; giving the paste at the right time helps make the drug more effective. Giving the dewormer a bit late because you haven't had a freeze yet isn't going to hurt anything if you're deworming six times a year.
I've also heard people have very good success with daily pyrantle plus ivermectin once in the spring and ivermectin+praziq in the fall.