Assuming 11" slicks and a fairly standard sized drift trike..
I'd say 5:1 and sleeves on a cent clutch should do well
On a TC you can go higher (3.5:1 and sleeves)
both will break traction with sleeves easily if you throttle up
But I recommend using split sprockets on the rear with a matching hub of course;
that way you can dial in the exact ratio as you go..
having a good ratio is -well- good; but having the ideal ratio is even better.
and that can only be found with experimentation
add a few teeth if you lack torque, remove a few if it's too much
until you can break free on throttle command and can stop the drift whenever you want.
that depends on weight as much as it does on engine power.
(how big's your butt?)
So yeah get a good starting point and if you feel you would need to adjust in either direction, buy a set of split sprockets and retry.
(don't forget to have enough chain

)
'sid