Are you looking for one rod to cover all three windows? That seems ideal, but perhaps you’re not going to be able to make it work here. Do three rods.

Are you going to have intermediate supports or are you expecting the curtains to stack all the way to one side?

How long are the curtains?

You will have to buy heavy duty traverse rods that have supports that do not interfere with the movement of the drapery across them, this is not something you will be able to buy in a store. I have a one piece ceiling mounted rod on one window and it is a little over 8 feet long so it had to be ordered by the person who fabricated the drapes and freighted.

A good quality round rod will work, if you buy extra center supports. I have an 8 ft round one in my living room. My curtains are not all that heavy, but, if they were the rod would hold them nicely.

It isn't that hard, you need to buy higher quality specialized rods (which you probably won't find at big box stores) and have them properly installed.

Have you looked at Kirsch products?

Hello, we got custom curtains with blackout lining sewed in.

Go back to where you got the curtains. Custom curtains are their business so they will know what you need.

Beyond that, we don't have a clue as to how the curtains need to be hung. Pleated, shirred, grommets... You said curtain 'rods' so the assumption is that you need three separate rods. That each window is treated separately vs two very wide panels. Is this correct?

Will the curtains be opened daily or almost never?

Thank you all for the feedback... I believe I leftout quite a bit of information while posting the questions... my apologies!

I have 2 panels of grommet curtains with blackout lining 108" in height, each weighing almost 40-45lbs ... thinking that I would hang them on either side using single rod. ... it's for a guest room but currently used daily.
I can't go back to the drapery store as it's overseas, not local to USA.

I hope this helps.

I first thought you might be able to use electrical conduit. It's very strong, so I looked for DIY info. Finding heavy duty brackets might be the biggest challenge DIY heavy duty extra long curtain rods