>>The problem is, I have absolutely no idea where to start, and the demo stuff
is way over my head. Would anyone be kind enough to point me in the direction
of a GWorld "walkthrough" for FBII (not PG), or even whip up something small
to show me the basics? I'm not using PG, and I know nothing (and I mean
nothing!) about COPYBITS or any of the other "GWorld specific" keywords I've
seen in the demos.<<

The happy answer is, you don't need to understand _anything_ about gWorlds in
order to use them; otherwise very few arcade games would ever get released.
Have you gotten as far as the folder FB examples: Handbook: Offscreen gWorlds?
Just copy  FN getOffScrnGWorld& and the group of FN's starting with
getCurrPort and ending with offScreenGynastics [sic] (add the others if you
don't like the way you're currently loading picts, or if you need to account
for b/w users). Paste them into your project & use as-is or with changes such
as:

--Instead of extracting the rect from the PICT as in the OffScreenGynastics
example, make your gWorld the size of the whole picture area of the window.
(Don't set the top corner of the rect to anything other than 0,0,--it may save
a little memory but it just isn't worth the extra hassle of working out
offsets.) Later, when you're feeling braver, you'll want to set up your
gWorlds just once & update them as needed.

--Look at copyOffScreenToWnd and notice how it uses the same rect twice. This
is where you'll be having fun: pass it two _different_ rects and you can start
working up zoom effects; pass it a copy-mode parameter such as _transparent,
substitute that for the default _patCopy, and you can put stuff on top of a
background; pass it leftoffset and topoffset parameters and use those to shift
the second rect.

Once you start getting gloriously fluorescent rectangles on your screen,
you'll know you're almost there.


Now, back to the earlier question--

>>passing portRec.top%, which is the first field in the record, has exactly
the same effect as passing portRec. It is just a little more confusing<<

Could Mars (or someone) kindly explain to me in words of two syllables why, if
_top_ is the first field in the record, SETRECT and all related procedures
start with _left_? "A little more confusing" doesn't quite cover it :-(