However, the merge is not so clean and results after the merge seem not to be in equal chunks (I have posted this on to my scratchpad).
I missed this bit of your spec: "(except for the very last chunk at the end of each block which might be shorter than 10 letters)".
Looks like you'll have to use Limbic~Region's solution of splitting the lines and storing the data as arrays.
Examine what is said, not who speaks -- Silence betokens consent -- Love the truth but pardon error.
"Science is about questioning the status quo. Questioning authority".
In the absence of evidence, opinion is indistinguishable from prejudice.