In all honesty, I've never vermin hunted with a 6.5-284. I have two dedicated varmint rifles, my 22-250 Rem and my 300-338LM. Well, my M-4 too, but that's for when they legalize road hunting Jacks in SD. (someday. . .)
The 6.5 I own I use as a deer rifle. That being said the 140 grain Honady SST bullets are quite brutal to an organ cavity and accuracy is excellent.
55 grains of short cut H4831 stuffed in a Norma/Lapua case with a GM210 primer and the bullet jammin the lands around .005" seems to shoot real well from my 1-8ROT Krieger (4 groove) barreled Nesika V action. Sub 1/3moa groups (5 shot). Velocity hovers right around 3100fps.
I've been to a number of NRA 1K any/any matches to include the US Nationals. The 6.5-284 has always done well. lately it seems more and more stoked up 6mm's are showing up on the scene too, but the 6.5 still holds its own.
If you ever have the opportunity, get behind a team scope on a firing line and watch the trace of a 308 and then observe a 6.5. It's a pretty impressive difference. The 6.5 will rise about half the elevation a 308 does while in its track to the target. Very flat shooting.
As far as vermin bullets go:
I speculate that if the chamber is cut for it and the twist is right, any thin jacketed bullet in the 140 weight class is going to work well. The rotational speeds of the bullet are quite high (around 290,000 rpm) and it's not going to take much to get that to come apart and make a mess of a critter. Especially a Yote'.
Hope this helped.