Farm house with low ceilings and Windows plus feature beams. The windows are very deep approx 28 inch deep. I'm removing the blinds.

I would like to put nice floor length curtains on or maybe Roman blinds but not sure on the following:

At what height to hang the external Roman blinds as I don't want them to over hang the Windows much as I would lose a lot of light

If I did go for curtains, what height to put the poles: on the beam or above or at ceiling height (ceilings are low). Do I go for just one pole to do both or two? Also I would need to keep the curtains back as far as I can so not over lapping the Windows much as again loss of light.

what do you think?

thanks