Handguards are Troy TRX VTac 9" on my 10.5 SBR and 11" on my Grendel. My 6.8 had the 11" and I loved how light they were plus the profile is just perfect. Keeping a pressure pad for the TLR-1 right above the VFG allows me to run the light if necessary and also give a place for my thumb to go if the MBUS need deployment. Having the light at 12 o'clock is like having a light shine directly into the FOV which means seeing your *target* faster. My only wish is that Troy would do a 10" version of the HG so I could have just a little more room to put the light forward and give some breathing room for my back ups. It'd also look better having the barrel completely covered, imho.
Maybe someday...
As far as the 6.5 vs 6.8 debate––-no debate with me. I liked them both alot. When I sold the 6.8 it was simply because I was offered $100 more for it than I had in it. It would've been used as a deer gun this fall but so could my 6.5G and both are lightweight enough that I didn't see a huge difference. Only reason I kept the 6.5 is because it shoots cheaper than 6.8 does with Wolf loads at $13/20. I could have reloaded 6.8 for that much but I'm also starting to try to figure some subsonic loads for my 7.62x39 and multiple set of dies and brass and powders all add up quickly.
If you're getting a midlength Grendel barrel you might consider keeping the barrel to 12.7-13" as that will give sufficient dwell time to cycle the action on your gun. And get a set of Troy 11" HGs from AIM. They're awesome.
FOREARM