I use Boge SR 3.0 at 4.2-4.6 on the buzz and Ipro and 4.2 on the ego twist. I also have some left over Resurrectors 1.7 and only use them on the ego twist at 3.7. IMO the Boge's SR 3.0 at 4,2 on the twist is about as good as it gets.
vaping SR on the twist will also save on battery life vs. a LR accessory.