By default RC creates one 8K texture. Your model is too big so you need to go to the Reconstruction tab -> Reconstruction Settings -> Coloring/Texturing -> Default unwrap parameters. In the settings you can change the Maximal texture resolution and Maximal texture’s count. For the best possible quality of the texture I recommend you to set Style to Fixed texel size and Texel size to Optimal. This way RC will create as many textures as needed for your model with the best quality. I highly recommend you to search “Adjusting Coloring and Texturing Settings” in the help directly in RC, all the settings are explained there.