Judging by players who have been reasonably involved at international level already, by 2018/2020 I reckon we will be picking from
GK - C. Bell, D.Marshall
DF - D.Wilson, G. Hanley, C.Mulgrew, L.Wallace, P.Dixon, P. Hanlon
MF - R.Snodgrass, J McArthur, B.Bannan, G.Dorrans, B. MacKay, F. Fyvie, J. Forrest, S.Armstrong, J.Murphy, L. Stevenson
FW - T.Watt, L. Giffiths, J.Rhodes, S.Fletcher, D.Goodwillie, J. Russell, S.Naismith, I. Feruz, D.McGeough, M.Phillips
Really hope we uncover some goalkeepers and defenders over next 2/3 years. I think midfield and forward options look good although most of these guys will be wrong side of 30 come 2020!