Before the thread gets derailed with definitions...
How do you classify an SMB from a DSMB? - DIVEIN.com
Common practice on SB is a towed marker with required flag is a “dive flag” and a marker deployed during dive is a SMB or DSMB (you will often seen the terms used interchangeably). As pointed out a SMB is any marker on the surface. You may also see the term safety sausage used, especially for the smaller markers intended to be inflated at or near the surface.
Since you are in Florida I will share the way Eric and I use our markers there. When we were very new divers and had never seen SMBs before the boat gave us small ones that we could deploy at the surface (safety sausage) if we separated from the towed flag. As we developed as divers and did surface away from the group and even more so were we started solo diving, we bought our own and learned to deploy at depth.
Eric’s preference is to shoot at the beginning of his safety stop. I like to send mine up just as I start my ascent. Personal preference and neither is right nor wrong. There are pros and cons to both.