bunch of advice:
standard trucks like indys are better for sliding than trucks like randals. The way they turn (compared to the lean of the board) is gradual initially and gets progressively more intense. this lets you break loose way easier, by snapping into a turn real hard. Randals are a linear turn, and its harder to create that intense and immediate turn in that breaks traction. they are really just better than randals for just about everything, but thats a whole nother story.
the lip profile of the wheel really changes its slide characteristics. if you have a square lipped wheel, and want them radiused, hook um up to a drill press and go at them with a file. a little bit is enough. try a little bit first, and slowly play with it till it feels right. Also, centerset or offset wheels are better than sideset wheels. thats mostly because they are less likely to cone out, but it also removes a bit of traction from the inner lip of the wheel, making it less grabby.
Soft bushings are key. if your back truck is dewedged, that'll make it more difficult to initiate a slide. sliding is all about quickly taking the wheel to the limits of traction, and then pushing it past. its almost impossible to slide a high traction wheel if you cant quickly get it perpendicular to your direction of travel.
any duro wheel will work just fine. its more about breaking them in correctly. if i recall, otangs are pre stone ground to give the wheel some texture. this is what kinda lets the wheel "walk out". a brand new wheel will flat real easily if you dont break them in a bit first. the best way to do that is just some simple colemans or pendys. the key is to slide while the wheels are still rolling. its also a good idea to slide it in both directions, or rotate your wheels at first.