Since the T/C Encore isn’t restricted to action length, I would choose the 280 Remington and 35 Whelen or the 7mm-08 Remington along with your 358 Winchester choice. All you need is 30-06 Springfield and 308 Winchester brass for either set of choices. This brass isn’t expensive at all compared to the 284 Winchester, plus you can also use military brass. Now .358 caliber bullets are very expensive, but you can find better deals on .284 bullets.
The 284 Winchester is a nice cartridge, but really shines when you are restricted to a short bolt action with equal performance from a longer bolt action cartridge. Plus the brass is expensive.
yooper77