Help! Photographing an eye...

Hi,

I am planning to photograph a close up of an eye...the iris. Very very close so that we actually see the textures with good lighting. Something like the attached image...

A photograph like the one attached but closer to get just the texture full frame without losing sharpness.

I am planning to buy the following equipment for this:
1. Macro lens: Canon-MP-E-65mm
2. External flash: Canon Macro ring lite MR-14EX

Would these be sufficient for the picture I want or does something better exist? I will be using them with Canon 5D...

Please do let me know. Would really appreciate any advice

Thanks,
Raaj