Just to follow-up...
The only way I eventually got in a couple rounds was through a friend's invites. During those rounds, there was no lag, slow loading, or meter problems.
And just to clarify... my original problems were slow-loading screens in the round-setup windows. And previous to those prob's, I had extreme delays during a round AFTER clicking my mouse on the meter (no meter stutter - just a "pause" after clicking it).
Why, after receiving an invite, I was able to play, is beyond me. I suppose it had to do with the communication between my comp and the particular game server I was connected to, as we've been told that they only come into play AFTER the meter is clicked. Incidentally, after those "invite rounds", I tried again to join a round, and had no better luck.
I have no idea why my computer was unable to download the graphics for the "round setup screens". I'd logged-out, closed browser, rebooted, and also rebooted my modem - all to no avail.
This morning, all is OK again. :/