Baffle installation questions

[spoot]

I'm about ready to install glass baffles in my standard 75 glass tank sump. I'm going to have the glass cut so that there is a 1/8" gap on either side to leave room for the silicone. I'm wondering what the best method of installation is. Should I put silicone on the side of the tank first and then place the baffle on the silicone? or should i place the glass in the right place then silicone the edges?

Also, what procedure should I use to install the baffles for the bubble trap? Do I need to do each piece separately? Thanks!