I would put enough mono to fill the spool 2/3rds up and put a 100 yard top shot of braid on top of it... 100 yards is plenty for anything inshore.
Best knot I've found to join the braid to mono is this one
https://www.youtube.com/watch?v=J56O3CZVu7M
The same knot I use the join a mono leader to the braid.
It's simple to tie, very strong and has a nice low profile so it slips through the rod guides nicely too.
