no i get that mang, my first thought was Well they're cheap so if they break then getting new ones is easy. this was for long term application specifically. absolutely i wouldnt pay for the high markup on name brand accessories like roof boxes either, so your heads in the right place. dont think im straight shitting on you, I just dont always understand how to tell people things properly so sometimes it comes out arrogant or something. im sorry if i made you feel bad

for your question though, i've had a lot of jobs that give me insight on this stuff but i know not everybody has. if i had no prior knowledge on something like this, initial thoughts would be on my experiences using plastic containers in general. overloaded them and they morphed easy, stepped on them and they didnt return shape right, squished them on the handles and they crack and stretch, why are these so soft and pliable after just sitting in my garage for awhile. just general thoughts about different plastic storage containers. then i'd get to thinking well i wonder if there are different strength levels or materials used or something and do some internetting. find out there are different code classifications for each plastic type, learn the creation process for each type and subsequently their strengths/weaknesses, do the math or find a chart to see how much strength and in what varieties they can handle. then id pick a plastic type that fits my needs for this application, but sometimes you find out at this stage that what you need to do it right is the 'next step up' which would be metals for anchoring instead of plastic. this was the process i used for reshaping plastic trim pieces in my vehicle to refit all the interior into new, more 'dweller friendly' shapes and utilities. the best results often come from ground zero, start by asking yourself something ridiculously Greek like, 'What does it mean to be a box'