Hey Dean, your vocal channel sounds fine. I don't usually do any announcements for each block as such. I do have the script in front of me while editing though. 

I also like to have the script in front of me while recording, that is handy. And of course if the talent screws up obviously go back at least a sentence or two when doing a re read. When this happens I make note in pencil on the script that it happened. It helps when editing.  Some VO talent will start a whole block again even if the error was towards the end of the block. That will usually be the one to use in the final edit as they will get the continuous flow right.

If you do re read sections or blocks more than once make a note which take the director thought was the best one at the time. Otherwise when you are alone editing later you can be wondering which take it is especially if they all sound very similar etc..

Great VO talent is a delight to listen to as well.

Funny you ask about the "Slates" or the "clapper-type announcements"

I use to record on a reel to reel.  The mixing board always had a slate/talk button that would put a quite, low tone under neath (App 100 htz).  I would say "OK this is Page 2, Paragragh 3,  Take 4."   The talent knew to take a breath and start reading.  I'd make notes on the script what was a good take.   So when I was editing I could fast forward the tape and count the beeps.  The low tone would fly by the playback head and make a "Pop".  If I took good notes and the VO talent was good,  I could edit a 10 minute piece in about 20 minutes.  Using razor blades and tape.

Not sure how you youngins do it today with the new fangled computers and their apps....

The last audio session i did was 1992. I was using a DAT machine. I still recorded the slates, but DATs would number the takes and ID them for you.   
 
I point this stuff out so maybe you can devise your own system.  There is no set protocol, create your own working procedure and talk to the Video editor.
 
The other guys have given you some real good advise.