If you have any doubt about a wrong bulkhead sent from pygmy, then call & ask them. I know you'll not be able to "tell them the exact form", but I believe they'll know to ask you the correct questions.

as for me. as always, I preffered the dumpster, there is a really good one around here, it yields great wood.

I never bothered to trim the wood, it's too much pain. I made the form from cardboard, I transferred it to the wood & the next step would be to trim the wood to the correct edges.

good luck

Erez