Backdrop tube

Need your help.

I am finally spending time in my garage and I am almost done. I mounted the backdrop arms like seen here:

link

I purchased this backdrop which I already had a look at and it seems great:

https://www.ebay.co.uk/itm/Vinyl-Background-2m-x-4m-White-Grey-Double-Sided-Phot...

The backdrop comes with an aluminium 50mm diameter tube. From the instruction, it appears to me that it was meant to be on another tube.
With the insight, ideally, it would have been better to buy three separate mounts and put them at the distance necessary for each backdrop.
50mm diamater (inside is around 48mm) is perfect for those wall mounts. However I say ideally, because for how the wall is made, I cannot put them closer than 2.5m between each other.
Therefore I had to find a solution to be able to mount the backdrop. This has been a pain, the reason is that obviously pipes come in standard size. Optimally I would have needed something between 45mm and 48mm but the closest was 40mm!

40mm is too small for those wall mounts, so I had to buy another 50mm pipe and join it with the 40mm to use as inside pipe for the backdrop.

It was a lot of work to reach a solution that didn't look flimsy, however I rather use a proper solution. What am I missing? Was the backdrop assuming that the wall mounts were at 2 meters between each other? Is there a standard pipe to use in photography for there cases? Or they assume that people mount these backdrop in those flimsy and cheap stands?

Go back to the Manfrotto site and look up Expan sets. They fit in the ends of the 2m tube and rest on the brackets you've put up. I suspect the instructions with the Expan sets will give the fixing centre measurements for the brackets.

I didn't understand the difference between the two yet??

I am not sure I understand what you are trying to tell me

If you are telling me that I need the plastic sticks bought the whole set. Btw it's not manfrotto as they are totally nuts with those prices. I bought this

Phot-R 3-Roller Wall Mount Photo Studio Background Support System - Black https://www.amazon.com/dp/B01AI09YSK?ref=yo_pop_ma_swf

The hooks are mounted at 2.5 meters distance and cannot be closer. The backdrop is 2 meters long. I need an extension tube that fits perfectly the 50 mm tube of the backdrop., Anything smaller would make the rolling mechanism useless

Wow thanks that looks great. Yes it's in a garage