Insert Read More "tag" after defined number of sentences and 1 image | CyberSEO Pro | CyberSEO support forum

I have checked the forum and am aware that a "Read more..." tag can be inserted from the PHP box which generates a read more url.

I am trying to achieve inserting a Read More "tag" after a defined number of sentences (e.g. 2 sentences) and 1 image from the post content. This would then display the template's default "Continue reading" linking to the full syndicated article on my website/blog. How do I go about achieving this? Possibly a workaround within the PHP code box feature?

Help would be tremendously appreciated. Thank you.