agree with boscomantico – unless there is a limitation in the AFM (which is the case for Zlin Z-142 for example) you can fly from RHS even as non-FI/CRI. But for a start, I would recommend to fly with someone capable on the LHS, it´s simply different. You´ll get used to is pretty soon but in my view it might no granted on the first flight.
Yes, matter of a few hours, and spend most of them in the circuit I’d say. And include some X-wind landings. I also believe it is useful to stay ‘current’ regarding RHS flying.