Well, I am now able to answer two of my own questions. Question #1 (about medium gardens) still stands as a topic of investigation for anyone with too much time on their hands, but I believe I have answered the two most relevant and important questions.
I have come to realise that there are a number of glyphs which are supported by the glyphgenerator but which have not been asssigned a convenient letter, number or symbol. I would like to call these 'hidden glyphs', because they are harder to make use of than standard glyphs. Hidden glyphs are more time-consuming to use, but they make the finished product look that much more professional.
There are a few simple stages to follow to use hidden glyphs in your glyphart:
1) Wherever you want to place a hidden glyph, insert a 1x1 building into your character input. wells and huts are good for this, since we rarely use them in our glyphart, but any 1x1 building will do. It must (or preferably should) be a building which does not feature in the layout you want to create. If necessary, replace that dentist/apothecary/police station with another firehouse/architect's post (you can change them back later). If you want to use a lot of terrain glyphs, I recomend allocating a building for each terrain (although you might run out of buildings if you go too over the top), and each storage yard should preferably be a block of 9 identical 1x1 glyphs.
2) Generate the HTML code for the layout. Make sure you have the right glyph directory at this stage as you won't be able to correct this mistake later on!
3) copy the HTML code into Microsoft Word or another similar program.
4) Start using Find and Replace. This is the laborious bit. Each glyph in the layout is converted into a tag which looks like this:
pharaoh.heavengames.com/strategy/tiles/architect.gif ALT="Architect"it's the highlighted bit which is important. By changing this bit we can convert any 1x1 glyph into any other 1x1 glyph. so by changing:
... architect.gif ...
to:
... plaza.gif ...
We can make the final layout display a plaza instead of an architect's post! The *.gifs for the 'standard 1x1 buildings are:
house1.gif
apothecary.gif
architect.gif
dentist.gif
firewarden.gif
juggle-platform.gif
roadblock.gif
shrine.gif
well.gif
And the 'hidden glyphs:
sy-top.gif
sy-tile.gif
sy-granite.gif
sy-pst.gif
sy-sst.gif
sy-lst.gif
sy-bricks.gif
sy-clay.gif
sy-straw.gif
sy-linen.gif
sy-wood.gif
desert.gif
rock.gif
goldrock.gif
floodplain.gif
meadows.gif
grass.gif
grassplus.gif (extra-lush grass - in humid climates)
So all you have to do is tell Find and Replace to find whatever you put as the 'placeholder' glyph and replace it with whichever glyph you want. For terrain glyphs, this is easy because you want to replace all the wells/huts with desert/grass. For Storage yards, just tell it to find "well.gif", for it to locate the first well. Replace this with "sy-top.gif" (this is the little awning where the stacker stands (always at the north corner of the storage yard)). Then find the next "well.gif" and replace it with whatever you want to put in the storage yard.
5) (optional) replace the pop-up tags. These are the tags which pop-up when you hover the mouse over a particular glyph. Just find "ALT=shrine" or whatever and replace it with "ALT=desert" or whatever.
6) Check you've got it all right. You can only do this by going to the forums, clicking on "post reply", copying and pasting into the text box, then previewing it. You can usually spot if you've made a typo because it doesn't recognise the glyph and puts "ALT=shrine" or something similar in instead.
7) Post and enjoy!