I taught on this subject today in conjunction with a series on worship.
The handout is here: http://www.hopeofchrist.net/teaching...Conscience.pdf
The audio is here: http://www.hopeofchrist.net/teaching...22-Worship.mp3
The goal of this was not to exhaustively deal with sphere sovereignty but to build a case for the limits on authority that God has placed on institutions and to unpack the idea of liberty of conscience especially as it deals with Worship.
I'm quite certain that my notes can be improved as well as my presentation but I pray it might prove beneficial to others as they learn these things or instruct others in them.