i've been been estimating how much weight i have left on the bot and i might have enough to add some additional bolt on armour on the sides i think i can get away with either 5mm thick cheep aluminium or 10mm plastic like hdpe, my main problem is which might protect better against spinners

i was looking at direct plastics at

hdpe
acetal
polypropylene
rg 1000


any ideas on which would be better, at the end of the day their sacrificial and they would have 3mm steel behind them so if they would all work to about the same level then i would just go for the cheapest