OP, I don't have experience with the 358-300WSM wildcat, but have a lot of experience with the 300WSM based on a Rem SA, with max mag length 2.800".
Looking at the Nosler Partition specs, the .308" 180 grain Protected Tip Partition - the bullet I use exclusively in my 300WSM - has an OAL = 1.180" while the .358" 200 grain Partition OAL = 1.175". So cartridge OAL shouldn't be a problem. The ABs are both significantly longer than either PT, so may pose COAL magazine constraints and/or case capacity reductions.
The Partition, especially the Protected Tip design, IMHO is particularly suitable for the WSMs, because of magazine OAL and chamber leade length design requirements. I assume that in IN you plan to use the 358-300WSM on WD, but the Partition design will produce very good nose expansion, despite the ability of the rear core to penetrate very well.
The sharper ogive of the ABs may work in the WSM chamber, but I'd be concerned about the COAL fit in the magazine. Just my 2 cents.
