If you want to use the Renault UN1 bellhousing you will need a 121 tooth flywheel balanced to your engine balance. If you want to use the 157 tooth SBF flywheel you will need a different bellhousing as the 157 tooth flywheel will not fit in a Renault UN1 bellhousing.
If you cannot find an adaptor plate drop me a PM via this forum (envelope at top of page) and I will send you a drawing. You can get one cut from thick ally plate by your local CNC laser cutter.
Cheers
Mike