Heaven help me - I've just bought a delta kit :-)

[curious aardvark]

first off - your bed is not that level.

Ideally you need all three to be the same, or at least within 1 or 2 100th's of a mm.
Not that hard, just takes a few g29s and some patience :-)
Running the first layer at 150-200% thicknss gets round that and doubles as a non-destructive raft.

Second make sure the little plastic bed mounts are really tight to the corner pieces. At some point I'll design a better mount that can't move and bolts directly onto the aluminium extrusion.
Then screw the springs down till they are really tight. This will help and also make sure your bed stays level longer.

No idea on the glass, never used glass.
Mirrors are supposed to be pretty good.
The heatbed itself should be properly flat, so use that rather than the glass. My printbite is stuck directly to the heatbed.

As far as the BB goes. Still waiting for some bits from china. Had a really good look at all the big and medium sized deltas (WASP make one large enough to print a couch or small garden shed).

So I'm definitely going for a flying extruder, probably even with a nema17 rather than my 14. There were some half the size of bb with that setup and no issues. The weird thing was they used stretchy rubber/silicon tubing to attach the extruder to the carriages. Possibly to act as shock absorbers in case the extruder motion effects the carriage movement. So I'll have a think about that. Might print some connectors out of filaflex.
Also, now changed the way I'll be making the magnetic arms and attachments.
Instead of the balls on the ends of the arms, you mount the magnets on the arms and the balls on the effector and carriages. Given my balls have threaded sockets (lmao, just reread that statement) that is actually very easy to do.
It gives you a much wider range of movement on the arms and considerably less chance of one detaching.

Also considering getting a more expensive arm based motherboard. Still no sign of eeprom on the gen base 1.5.
Worth going to the show for those few things alone.

My printbite is on it's way, still need to pop over to jsk and get the base plate and aluminium bed made. Might need to make the bed mounts first so I know where the holes need to be drilled.

Currently got some actual paying work - wahey !
So bb not a current priority.
But, yep the final design is almost there in my head :-)