Using the anti-twist plug on waveboard... or not ?

[Anowan]

I recently got myself an Evil Twin 80, the lack of conditions to try it got myself thinking about trimming the board correctly.
Now I have one anti-twist plug missing in my accessory bag (the grey one containing the straps, screws , stickers and such). Also the 2009 waveboards back straps are now attached to the board via 4 inserts instead of two, but the anti-twist plugs are too wide to be placed side by side, they sit one on top of the other.
Meaning I would have to sand the plastic of the two closest plugs on one side so that they could sit next to each other .

But since I have one plug missing anyway, and that there are 4 inserts instead of two (preventing the backstrap from twisting in the first place), is it reasonable to just get rid of them for the backstrap ?
I'm asking because I heard the 2009 screws are longer this year, therefore going deeper in the insert, so I naively wondered if that could damage the board if I used the longer screws without the thickness of the antitwist plug...? (I know, just being extra careful with my new precious toy).
Or would it be wiser to just order a new plug at my shop, then go on with the sanding of the plastic ?

Thanks for any advice on the matter (unfortunately I'm not in a hurry to mount the straps yet, the forecast at my spot are low to no winds, with temperature below zero celsius, brrrrrrr)