Is the IC you have shielded? If it is, one end of the shield will be floating, ie not soldered to the RCA connector. Therefore you cannot simply cut the cable in the middle and soldered the leads to your turntable. You will need to connect the floating shield to ground on both halves of the IC.
Given that you plan to use it as a phono cable it would make most sense (at least to me) to ground the shield on the TT end. Thus you would need to figure out on which end the shield is grounded at and then somehow disconnect the ground, by de-soldering the shield from the connector (if you can access it without ruining the cable)
If the cable is not grounded then you are good to go, but you may not want to use it as phono cable.
as for your other ideas, I would not make a cable much shorter than 3ft. Shorter cables may work now, but if ever you want to add or changes components such as add a separate phono stage then shorter cable may no longer work.
I hope this helps
Given that you plan to use it as a phono cable it would make most sense (at least to me) to ground the shield on the TT end. Thus you would need to figure out on which end the shield is grounded at and then somehow disconnect the ground, by de-soldering the shield from the connector (if you can access it without ruining the cable)
If the cable is not grounded then you are good to go, but you may not want to use it as phono cable.
as for your other ideas, I would not make a cable much shorter than 3ft. Shorter cables may work now, but if ever you want to add or changes components such as add a separate phono stage then shorter cable may no longer work.
I hope this helps