Can I put up additional u-turns to a photobook template that has already been posted for sale

I sell a photobook template that includes 10 spreads. The book is made in two versions-light and dark. I have prepared 15 additional spreads for this book in a dark version. I don’t plan to make light u-turns. Please tell me how best to place these extensions on sale.
I have three options:

  • Remove the light version from the existing product and add additional dark u-turns. A light option to put as a separate book. Will they refuse to do this, since the light and dark versions differ only in the color scheme? And also because the light version was already laid out earlier.

  • Lay out 10 old u-turns and 15 new ones as a new independent product. And leave the old one as it was. Will this be refused, since the u-turns of the two products will be identical?

  • Put 15 new u-turns as an independent product without a cover, indicating that these u-turns can be purchased as an addition to the template that is already being sold?

If not one of the options is not suitable, can I sell my 15 additional u-turns outside of this site, being the exclusive author?