Some guys remove them partially as you have done, or completely. I opted to trim them back and 1) welded reinforcements to them that are tied into the backdate bumper mounts, and 2) made brackets that will both support the ends of the new bumper as well as connecting to the headlight bucket and stabilizing the fender. I used threaded rod so that I would have adjustability, and to be able to pull the bumper and fender joint together with the seal in between.
Trimmed:
Bumper mount reinforcements:
Support bracket for new bumper and fender:
