Not sure if the Inty you have is UK/PAL or imported, but if you're from the UK (like me ), then RF for any US/NTSC import is only possible on a world standard & typically older TV/VCR with US tuner - most newer UK TVs left with RF only seem to have PAL analogue tuners (will show I on the analogue tuning menu) even though they are happy with NTSC colour signal & 60hz!
Either way, composite will likely show an improvement (clarity wise) over RF on a modern TV so I would go that way if at all possible & gives you more future proofing on connectivity (BTW mine was an import, already modded!)