Hot Max 24011 Flashback Arrestor Set, Torch End

Should i remove the check valves that are already on my torch body to install these?

Should welding flashback arrestors be installed at the torch end or at the regulators?

Has anyone using this and the regulator end arrestor experienced increased backfires, possibly due to pressure drop? How did you compensate for it?

does this go one the tank or the torch end?