This from Blake T for the sidearm bit is superb. It gives you such a simple way of throwing sidearm. Just by sticking this on a horizontal plane you should be able to get good distance then work on adding more body rotation to build on this.
The beauty of Blake's drill is it will stop the wobble and give you a firm basis to work on building the distance.
When you do it properly and feel the bounce at the end it clicks so quickly.
A number of friends over here struggled using the videos Blake posted plus the write up (don;t ask me why i thought his little series was incredibly easy to get, I suspect they didn't bother reading it....) so I made a vid for them putting my own slant on it. Adlibbing as ever I talk some crap in there but a number of people have found it very helpful in increasing their distance but more importantly control. (Hope Blake doesn't mind me having done this
My sidearm is incredibly reliable up to about 80 meters with good throws now going over 95 and if i really crank it on an open field over 110 (no control with these at all 1 in 10 will go well the rest would be awful trying to get to this distance) I practise and play pretty much never since a case of Babyitis with another one on the way, but I know going to the course once every 3 or 4 months I can rely on the forehand to immediately fire just by replicating this drill a few times before throwing.