I was originally getting prints like on the left (each piece is oriented to show it's worst side).  One lesson: I think I had whacked the bed out of level while doing all this, which led to various issues (and had me going down many false paths -- doh!).

Not quite sure what did the trick (my approach wasn't entirely scientific here, I was changing too many parameters at once), but since it works, I won't try investigate more for now -- but if any experts have any comments on what I might be doing wrong/right, I'd love to hear them.   After reading a few more posts, I'm a little worried about the anti-backlash I installed -- do I run any risk of binding and damaging z-axis motor?  I've run several 1+hr prints with it, and no problems so far, but...

Pretty happy with the machine!!

(edited 6/9)

1. Parametric spool holder ( thingiverse com thing:91477 ) : Original PVC pipe was functional, but made it hard to place printer.  I found some spool holders, but they were hard to print (w/o fan and w/o supports, which I hadn't discovered at the time), so I designed something simpler.  The design is parametric, so you can change length, angle, mounting positions, etc.  I haven't tested all configurations, so let me know if you try and something is not right.

2. Raspberry Pi enclosure ( thingiverse com thing:99300 ) :  Now that I didn't need the spool holder clip, I re-used those mounting holes to mount a RasPi running OctoPrint, so I can print without my laptop via a web-browser.  At $35, I think it easily beats any LCD panel solutions.  Works great (just had to tweak OctoPrint's connection timeout, which is 2sec by default -- 10sec seems to work for the Solidoodle, with the factory FW).

3. Well nut anti-backlash ( thingiverse com thing:100053 ) :  I was lucky to get the new aluminium platform.  It had minimal backlash, but I started having some minor issues after I calibrated extruder (out of the box it was over-extruding slightly).  None of the previous anti-backlash tricks seemed applicable, so I modified an idea by pirvan in this forum, using a $2 well nut.  Did this last night, seems to work fine so far.  Still having some outer perimeter vertical alignment minor issues (always at back-left for some reason, but even with moderate size prints, and even at half-speed -- will try tealvince's x-axis preload this weekend) but, other than that, perimeters seem even better now (small difference, though).

I've also installed a fan, but having some extruder temp issues (I'll post a separate question, once I get a couple of temp curve screenshots later tonight).   By far, however, the best mod was also the simplest: a piece of glass and hairspray.

Hope ppl find at least some of these useful, and I'd love to hear feedback, if any.

Cheers,
Spiros