Difficulty in LED swap focus/beam

Hi, I hope this is the right place for this.
I have a few lights by now, and in swapping out a bunch of LEDs, I seem to not get good beams sometimes.
Latest is just a DX Q5 star into a rayovac 3C to see if Q5 could help.
The beam now has spill, and not much brighter if at all from the original Cree in there. I noticed a rubber o-ring around the original, and did swap that, but does anyone have a way to test or check and tweak the beam?
I assume spill now (it has an optic) means leaking or the LED is too far from the optic?
Also, similar situation with a Cree in a lumileds Advanced auto light (I sort of expected some problems there).

Is this easily fixed maybe with a snap on smaller optic like I have seen on cutter?
Or possibly a reflector unit like I have seen on some of the multiple Cree modofieds?
Thanks, Please offer pointers if there are any. Maybe it is just extremely touchy to get the right focal spot on these swaps.

The original LED probably had a lower VF then the new one which would result in less light from the new LED.

If you have more flood from the light now you need to adjust the position of the LED.