Audience Size for Experience Targeting

Hi Community,

I have been running an XT where I have 4 different experiences created for the Home Page banner, which is defined for different audience groups. We are using the 6Sense ABM tool where we have orchestrated 6Sense segments via 6Sense-Adobe Target integration to use 6Sense segments as the audience in Target.

Questions:

-> I am not sure if that is the reason I can not see good conversions (CTR) on my home page personalized banner as I am using a different tool for audience definition. 

-> In general, How would I know the audience size is okay for the experiences that I have created? Usually, we use analytics segments in Target. But this time we used 6Sense.

-> How to expand the reach of the experiences to the right audience?

-> How to improve conversions?