Jacob:
It's a good start.
WRT OGR -
I always sand or trim the side walls to make sure they are as flat as possible. Just make sure the mold sprue residual is removed. Sometimes the front and back walls will have a slight bow. This is normal and can be compensated for during blue up. Just use as many clamps as you can - minium one top, one bottom, one center. I usually add two more clamps just to be sure.
To help insure a flat perpendicular joint I also use 1/4 inch sq styrene in all corner joints to increase glue surface.
WRT Downtown Deco -
If you bought directly from Downtown Deco / retailer you should ask for replacement walls. Some breakage is expected with hydrocal walls but what you have is somewhat excessive. Downtown Deco usually does a great job packing for shipment. If you bought from a private party then that may explain the breakage. Perhaps you can purchase replacement walls from Downtown Deco.
I have attached a set of instructions I send to customers who purchase kits and ask for assembly hints. Hopefully this will be some help to you.
Good luck
Joe
