I’m assuming the intention is to go all out for a win in this final test.

The problem is India only need to see out the next couple of days for a draw and a series win.

So the question is what’s the lowest total Smith would be prepared to give India to chase?

It will have to be something absolutely tempting to get them to abandon their current draw motivations.

220-240 with 60 to 70 overs left?

You have to give them a genuine total they can reach imo

Maybe even lower? 180 in 50 overs? 150 in 40 overs??

Would require some clever batting ie plenty of time at the crease and hardly no 4s or 6s. Just singles until you get to the right set up you need for the chase.