I recommend foregrip w/ extended mags. If you must use the blue dot then go for it, but the iron sights are not bad on the HB. I focus on the green dots and make sure the enemies head is level with them. As far as your question here are the perks i would use (cant have the ied or grenade with this many equiped, but you wont really need those)
Stalker, Ready Up, Quickdraw, Focus, Amplify
If you do not have a nice headset do not use Amplify, you can exchange that for Ping or Dead silence. My goal with the HB is to be mobile and mid range. If caught while in the middle of moving Quickdraw and Ready Up help a lot. I cant aim w/o stalker. Focus keeps my aim from bouncing. Amplify + a nice headset = mobile camping. I hear them and i can surprise them while they are sprinting. Dead before they even get their gun up.