SD2 bed dimensions

In theory you can print the whole 6x6 area of the bed.  You will likely encounter warping issues (among others) when you do this though as the bed is not evenly heated. 

If you are going to be printing many things 6x6 then you might consider trying to upgrade to an SD3 before they ship you your SD2.  Otherwise you are probably going to get frustrated making a 6x6 bed work for your application.

In my opinion, you'd lose 4mm across all edges (making the total usable bed size ~142mm or ~5.5 inches square).  This 4mm would be used for a brim to make sure you don't warp or curl the print.  You could conceivably shrink that to 2mm (or ~5.75 in sq) for the brim, but I'm not sure that you wouldn't get warping.

A suggestion made by a user was to use an acetone-ABS slurry and paint the part edges after the first layer (pausing it so that you could apply it).  This does work, but you're in for a bit of work to apply.  This would allow you to go to the max edge without a brim.  YMMV...

Oh, and don't worry about igniting the acetone.  I paint a hot bed all the time and I haven't set it on fire yet.

The slurry is just a mix of acetone and ABS plastic.  I use the discarded brims and extrusion tests (the stuff you get when you feed new filament through the extruder) to dissolve into the ABS.  Since the pieces are thin and small they dissolve quickly (usually within a minute or so).

It's not really a science, but I melt enough so that the mix gets pretty milky and opaque (probably about 2 oz of acetone to about 2-3 g of ABS) but YMMV... The acetone evaporates leaving the ABS in the mix to bond.  This stuff can also be used to bond 2 parts together and holds better than crazy glue since the plastic in the slurry bonds to the parts while slightly melting the part to form almost a contiguous piece.

Hope it helps.

PVC isn't going to do it... you need ABS, the material you're going to be using to print with.  In this case you'll have to wait until you have the ABS to use unless you know someone who has some to give you.

I paint my bed every time I get a clear spot on the glass (and you'll want to do the glass mod as it will help with the bed leveling + you'll be able to swap out pieces of glass for faster part turnaround).  This occurs when I do larger pieces and it pulls up the abs I've laid down.  For smaller parts I don't usually bother.

So long as you keep it covered (and the container is airtight) it should keep for quite a while.

The glass mod mentioned above is simple.  Go out and get a couple pieces of glass the size of your bed (6x6 in this case) and a couple of binder clips, then clip the glass to the steel bed.  You'll need to re-adjust your z-level so the bed is level and it doesn't crash into the bed and crack the glass.  Doing this immediately will allow you to level the bed before you even start printing.  Some people use hairspray on both the top and the bottom of the bed (top to get the print to stick to the glass and bottom to get the glass to stick to the bed), but if you plan on using the slurry and binder clips you won't need to use anything like it.  You'll find that it's the most useful and economical mod you'll find.  Search the forum for 'glass' and you should find more information.

Check your PMs...

I does stick very well. Sometimes too well. But that is why I use a razor scraper. Even the most stubborn print comes off quickly and fairly easily.