re: SMB and finger spool.
First, I would not recommend diving with a spool to a new diver. There's enough that needs your attention to begin with, without having to fool with deploying a buoyant device from depth without messing up your position in the water column or getting your line twisted around someone else's.
Second, I would recommend going with a small SMB so you'll have something to wave if you're bobbing at the surface.
I've gone several entire trips during which the only time the SMB and spool came out was for rinsing back at the hotel. On our most recent trip, I used it for over half our dives. The difference was that we were diving with a newly-certified nephew who had to surface well before we were LOA. In some cases we stayed at depth for over 20 minutes after everyone else had surfaced. Other times we've deployed have included in some unexpectedly rapid currents when our group ended up very spread out.
Most of the time we're right with the DM so don't need our own SMB.