Keep the transformation of data for another data sets

Hello Clout 

this are a lot of question. If you find a logic to transform your data, in PQ you can do it. About your question of keeping rows you could create a list of column names and then keep only them, so you are able to build a manual list and PQ keeps them automatically, so you don't need to dig into the code. About your question regarding removing empty rows at the beginning you can check my example here

let
    Source = Table.FromRows(Json.Document(Binary.Decompress(Binary.FromText("i45WUorVwU6kZRYVl4BZKYkliWBGUX55sVJsLAA=", BinaryEncoding.Base64), Compression.Deflate)), let _t = ((type nullable text) meta [Serialized.Text = true]) in type table [Column1 = _t]),
    #"Changed Type" = Table.TransformColumnTypes(Source,{{"Column1", type text}}),
    RemoveFirstEmptyRowsInColumn1 = Table.RemoveFirstN(#"Changed Type", each [Column1]="")
in
    RemoveFirstEmptyRowsInColumn1

Copy paste this code to the advanced editor in a new blank query to see how the solution works.

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Have fun

Jimmy