You'll either need to:
1. drive out the hammer pin where the hammer connects to the hammer strut (may need a special hardened punch), a new pin to then install the hammer strut to the new hammer. I did this awhile back and had some hammer/pin diameter issues. I beat that pin till it mushroomed and it would not fully seat/insert into the hammer. I finally filed off the "head" of the mushroom. Sometimes pins/holes in the hammer aren't the completely compatible. Oh, also damaged my hardened punch during that job.
2. buy a new hammer strut and pin to use with your new hammer. That eliminates the job of driving out the original pin to use the old hammer strut with the new hammer, but may not eliminate a pin diameter issue.
To be honest, I've done this 3 times and only had this one issue, so it may be pretty rare.
The adjustable sear does make it quick/easy. I'm only "fit" one new safety to an old sear. I took that safety out 24 times to remove small amounts of metal from the cam before I got a proper fit/function. If you remove too much - your safety is unusable, so if you file/stone that cam, go slow and check for proper function. Oh, you'll need some Loctite for the adjustable sear (I used the blue Loctite.)
I don't know that the safety/adjustable sear is related to "camming" of the hammer. Isn't that a sear/hammer fit issue?
Anyway, that race hammer CGW sells is great. We've used a couple of them now. Awesome smooth break after installation.