The .264 is a good way to go but it really depends on what you want to do with the rifle and what you plan to kill with it. I made the mistake of THINKING velocity was important, and really, it's not. Energy delivery, and reduced wind drift is FAR MORE IMPORTANT TO ME as a shooter than speed, because I enjoy shooting beyond 800 meters.
If you don't want to utilize the features the 264LBC was designed to retain...then you might as well stick to the WSSM.
The 264 lbc can shoot at 123 scenar around 26-2650 fps, retain supersonic flight beyond 1000yds and still deliver nearly 500# of energy at 900 yds. However, if you're only going to shoot coyotes, the supersonic range ability, and energy delivery of the 264 isn't necessary, and the shorter lighter bullets will fly better out of the WSSM due to better ballistics at higher speeds.
The 243WSSM shooting a 105 VLD at 3000fps will deliver similar numbers (supersonic beyond 1000 and nearly 500# at 900yds)...but good luck reliably loading them in a WSSM case.
The WSSM will have a VERY hard time delivering 500# beyond 900yds and retain supersonic flight beyond 1000 with anything other than heavier VLD bullets, but again, if you want to stick below 100 grains...the 243WSSM is my suggestion. 87 VLDs, 85game kings, 87 VMax or Hollow points. Very good, flat shooting fast bullets in the WSSM