Curtain track and blocking light

[Lat321]

Hi, looking to find a solution to a problem we have long been ignoring..

We have a bay window where we currently have bqdku fitted roller blind and a pole. Both in need of replacement.

I was looking at ceiling mounted silent gliss tracks.(stupid) Questions are:

1. Does the curtain stay below the track i.e.there will be a gap where light will get through.

2.its a North facing room so gets cold in winter. I was rhi9iabit worth getting a double track curtain?Had anyone got double curtains? If so, any feedback?

Many thanks

Think ours are Swish make but ceiling mounted. We have thermal lining. Not much light at the top.

If you have problems with light you can move the curtain hooks down