i feel your pain..

look at it like you had to make the part all by youself in the first place.
and now you are making the final fit the best way you can.

it might mean making a slice to make the ends mate
and filling the gap in with new material or adding material
on to the end to make it meet up properly.
or it might need to be bent into place.
i have used all 3 ways myself,

even getting a 2nd or 3rd part!

i should do a bbody rear deck filler review someday
goodmark vs amd...

you always have the option of getting a original one
that will fit like a glove.
it does makes you want to smack the tard who says amd fits better then nos

all i can really say is
if you post up some pics
someone might have a good idea for you..