Koppen has mentioned it a couple of times. I can't recall style, but there were three categories of players ('The recruitment strategy will continue to focus on a balance of core, investment, and impact players'), that would mix youth and experience.
Jefte, Nsiala, Fernandes and Igamane are projects and investments.
Cerny and Propper are impact players; quality or experience to give the team a boost. Propper may have been a personal contact but still fits the profiles outlined.
Scots, like Barron, Souttar, Kelly, Cameron are more core players and investments. The plan is to sign at least one Scot a year, IIRC?
Core players would be Diomande, Bajrami, Kasanwirjo, Kelly maybe?
I've been happy with the general approach, but I have been critical of the lack of first-team players of quality.