I just shoot my first 3d which happens to be a Mac shoot. I am now in MBR but would like to go to MHM can I do this or will it be an issue? If I can change what will it do with my MBR score?

I think you can shoot multiple classes. Your MBR score will stay in the MBR class and will not be used MHM. It probably only matters if you are going for shooter of the year.

I would like to go for shooter of the year but I really don't think it will matter much this year. Now for a sight can I use a sure loc with a specialty archery scope with an up single fiber and just take my lense out?

You can find the rules here.
http://www.midwestarcherychampionship.com/2009%20Rules-Posted.pdf

Just suck it up and go MBO!:peace: