Just a suggestion: I don’t think your data looks that messy. Writing one or more RegEx to extract all dimensions correctly might be a challenge, but it shouldn’t be too difficult to come up with a RegEx that finds a relevant substring of size <60 in a longer text, which you then can give to your existing LSTM.
The RegEx doesn’t even have to be that specific since it’s just a preprocessing step. For example: All substrings containing 3 numbers. Then you include the 3 word before and after that substring and check if it’s below <60 tokens. That should do it.