Not understanding the Censor Effect in FCPX

Very much a newbie here (only prior experience is iMovie 6HD).

I am trying to utilize the censor effect within FCPX to hide a tag number on a vehicle in a video clip.

I actually haven't been able to find ANY instructions on using this effect, so I may be doing it all wrong.

So far, here are my steps;
1. I use the blade tool to select a bit of video that I want to apply the effect to.
2. I select the clip to be edited and then drag the 'censor' effect icon onto the selected clip and drop it.
3. Use the clip drop down menu to select 'Video Animation' and then the embedded drop down menu to select 'Censor' and then 'Center.'
4. I create a keyframe within the censor animation timeline (at the beginning of the clip). With the keyframe selected I move the censor effect to where I want it and adjust the radius.
5. I then continue along the censor video animation timeline creating additional keyframes and moving the censor effect to continue hiding the tag number as the vehicle moves across the screen.

When I'm done and I preview it the effect seems to work well and follows the tag I need disguised.

Question.
I assumed that with each keyframe selected I could not only adjust the position of the censor effect, but also the radius. However, it looks like if I adjust the radius at any keyframe then it applies the new radius size to all the keyframes - however the position of the blur effect can be different for each key frame.

I really need to adjust the radius also because the vehicle gets further away and I need to make the censor radius smaller as the vehicles gets further away.

Any ideas?

Do you have keyframes for radius option also?

Ahhh. So, I have to then go back and do separate key-framing for the radius after I've done it for the center? I just relooked at my project and selected 'radius' under the Video Animations > Censor > Radius menus. I see where the center timeline goes grey and I can create new keyframes for the radius now.

I just assumed I could adjust everything in the same keyframe and timeline at the same time.

Yeah that was a feature previous to FCP X. Set keyframes to a parameters and auto add keyframes over time.

I hope this will be back in the next version!