Curriculum for English for K-6 for US

We are working on development of an online learning portal to assess the student's efficiency in English and then teach them various topics of K-6 curriculum of common core standards in the US. Based on an initial assessment we can gauge the student’s strength and weakness in a particular topic of his Grade level. Then we provide customized training based on his strengths and weaknesses which include videos to learn the concepts using different pedagogies and practice worksheets with increasing level of difficulty to make him understand the basic concepts and challenge them with critical thinking or more advanced concepts. The practice can be done online or paper-pen. The student would progress to the next level of difficulty in the topic once he has mastered that level. We are looking to getting an experienced English content writer to create such online content (worksheets) for our students on English language for K-6 grades. We expect each grade to have atleast 2000 questions to avoid repetition while taking the worksheets online. So we are looking at a total of 12,000 questions. We would follow the common core standards curriculum and would insist on working with people who have previous experience in US teaching environment and/or development of content. Please attach your previous work and experience and quote for development and delivery of content per grade. The final content would be expected to be entered on our system online. Please PM me in case of any queries