I needed to mount a curtain pole in the internal reveal of a window, and Ikea's Hugard fit the bill. 

The Hugard has different diameter pole's at each end, hence the two models.

I was also wanting to find a way to use the mounts to hold the last ruffle in place, so there is another option attached with a 40mm flange to assist with that dilemma.

To help with aligning both sides, I've left a small centre hole, so you can measure a point symmetrically, and then used that to help set out