Thank you very much, Jumanji! Much appreciated and duly noted.
I was not planning on installing any programs on these HDDs and now I will not do it for sure. This is a "production machine", so I am very selective with what I install on it anyway. There is plenty of space on the SSD, and should I run out of space, I will migrate to a bigger SSD, which I personally think will not be needed for the life of the machine. There is plenty of space on the SSD, and I will really try to keep as much space free on the SSD as possible to maintain speed and longevity of the unit (which is perhaps more of a myth) - but an empty SSD is faster than a full SSD from what I read.

Thank you very much once again for the advice and time taken to answer me. :)