spark plug rethread question

I rethreaded a horribly chewed out spark plug hole on a snowblower using a kit similar to the picture.
After reaming out the wider hole, I put the insert on the plug finger-tight, then put the plug in the hole. After unscrewing the plug again, the insert remained in place in the old hole (seems Ok so far, I think).

Now I have concerns:
1. Should I have loctited the insert to the head?
2. I never did use the long tool in the kit, I assume its used to pound in at the end to smooth the top of the hole? But its too late now as i cant remove the insert unless I force it out, and probably damage it, and would have to buy a new insert (my kit only had one of each size).

I assume once I torque down the plug it will seal good enough, or do you think those steps were critical?

 

Insert should bite in a little, I would use strong Loctite unless the install recommendations say NOT to.........

 

The kit came with zero instructions.
It did seem to bite a little as the top two threads on the outside of the insert were slightly sawtoothed.
That was the "whoops its in there now" moment as I was playing around with it.

I think I'll torque down the plug, and hope it seats alright. Then with luck I wont have to remove it for a long time.
Worst case scenario (hopefully) is the insert could always be taken out one way or another at another time.