Hello new member first post.
I still would probably have Brown ahead of Shankland and think Clarke may well too.
Shankland's form is excellent but the Scottish Premiership is a really awful level and not much of a barometer of anything. Plus, Brown's physical attributes are far better suited to Scotland who generally only play one up top. He also can play wide so offers more versatility.
Shankland's best chance is the fact that the times he might be used by Scotland would be when we were chasing a game late on and might want to go to two up front. So that would suit him better. Shankland, however, is best facing goal where our strikers generally need to be good with their back to goal and that suits Brown much better.
With only a 23 man squad Brown's physicality and versatility put him ahead of Shankland for me. Shankland scoring goals against St Johnstone and St Mirren doesn't change that.