Managing dataset import and export with excel, csv, sql ? best practices ?

sorry if this is potentially a stupid question. i'm having difficulties finding useful threads, not sure how exactly which terms i should search for.

i have different collections of data, either as spreadsheets (single workbook or multi workbook) or text files and i want to use them to construct or transform in GH. Ideally once the data has run through my grasshopper network i would also like to export/save a resulting set of data also as a spreadsheet or text file.

googling this i came across the reference to ghowl in the 'Common questions' thread. the component seems to be rather old so i'm wondering if it is still used or if there is another way to do it. i've tried using ghowl and also the 'Read File' component but can't seem to make any sense of it.

I've attached a sample excel file to illustrate what i'm trying to do, in this case it's just a collection of different guitar string sets. each worksheet is one set, divided into 6 strings with gauge and tension values. i would like different values in different places in my GH network. I could o f course have everything in one worksheet, or one file for each set depending on what makes sense.

how would one go about something like that ? what would be the best file type and formatting of my lists to make this work easily in GH? i could also have the data in a database (mysql preferred) if that is easier.