I have some thoughts on the side arm.
Although I haven't given it the time to learn it's full potential, I have found it most useful when I keep it simple.
I've been using one now for a couple of years and every time I try anything other than a steady paced top of off stump line, there's a chance it will be unplayable, dangerous or both.
Being left handed, if I become complacent with it, my heart can skip because of the angle into a right hander, but thankfully so far only the odd bruise.
I don't enjoy bowling, it hurts too much, but I want to help so I got efficient at the side arm.
There's a knack to it no doubt but don't be put off, I sure wish some of our other players would try to learn, top of off stump sure would be nice compared to some of the dross that we all get served up from time to time.