Both necks will probably feel bigger than your Ibanez. The J will be very close. The P will feel allot bigger.So, apparently the bass I wanted to buy (another brand) is not available and my sales place has given me the choice between these two models.
My concern, I cannot hold or try either before purchasing. I currently have an Ibanez SR300EL. I do not want an overall thicker neck for a second guitar. Can anyone compare the necks of these two for total circumference? I’ve read that they both have the Modern C neck. They both have a 9.5” radius. The P doesn’t taper like the Jazz to my understanding.
A Soundgear neck and Precision neck are almost polar opposites.
That said, the Jazz is also likely to be much heavier than your Soundgear.
So of the two I'd say jazz but how important is weight to your comfort?
Despite your situation I have a hard time recommending either to you. Fenders and Soundgears are pretty far apart in ergonomics weight and design.