Absolutely stunning signing! With Slater and Ness that's good enough for challenging League 1 title, let alone a League 2 title. However, with their injury records it is quite possible they'll both be out together at some point which means a midfield of Archie Thomas (decent enough) and Harkins (not great!)
Irvine may choose to mix up the team for Saturday but back in the league he may opt for this type of formation.
McCallum
Meechan, Munro, Anderson (or Travis), Strachan
Ness, Slater, Thomas
Thomson, Aitken, Crossan
With that midfield 3 being fluid so it could be a 4-1-4-1, a 4-2-3-1, or a 4-3-3 depending on who we're playing and how the game is panning out.
Aitken (if his form is down) could easily be swapped with McCluskey or maybe Shepherd.