Just use a good quality clear Nylon or Co Polymer. They can be significantly cheaper. The east coat fish would not be able to tell the difference in the murky waters where they live. There is even debate on whether trout (a extremely wary fish) living in crystal clear spring creeks notice the difference between the two.
Flouro also has worst knot strength. The only advantage might be slightly better abrasion resistant.
I am not a big fan of Black Magic products but their leader material is common and good. Sufix is always good, I believe they make the lines for many other brands. Heaps of good options out there.
ginga, if you have two spools. Put all of the braid onto one of the spools first then tie on the mono backing and wind it on until the spool is full. Then transfer the line from the full spool onto the spare second one. That way all of the nylon would be on the bottom and the braid would be on the top.