Integy sell something similar too, as do a few other obscure places (FastTrax?)- I believe he wants plastic specifically though as its less likely to bend and get damaged compared to the beautiful metal arms..
But what is the long screw in the middle of the front upper plate doing there?
And how did you make / where did you get those dirt guards for the batteries?
I would wager the longer upright screw it to wrap the rx antenna around, and the ones holding the shocks to the towers are because he couldnt find hex heads long enough? I know I had issues but managed to get some after a bit of searching..