Flooring Tile - Threshhold problem - carpet to ceramic

I just installed a ceramic tile floor on top of poured concrete. The previous threshhold was this cheap-looking, fake-gold piece of metal that held the carpet and was fastened with concrete nails.
After installing the tile and using a 3" overlap with the carpet, how can I now fasten a new threshhold ?
Technically, I could zip-off the nails in the old threshhold and just use a fastening caulk to fasten it to the floor.
However, I bot a 2 1/2" wide threshhold from the Home Depot that has pre-drilled holes. It's nice because it matches the tile. But I cannot use tapcon screws, the heads are too large (and an ugly blue color !).
This is a PAIN. Any ideas as to the best carpet-to-ceramic threshhold fastening ? Especially when concrete is below ?

No one ? Surely someone else has encountered this one before.

Tapcon make a phillip head screw. You could use a countersink for the head. Use a putty to blend it all together.

Drill holes in the slab that align with the predrilled holes in the threshhold you bought. Install plastic anchors in the holes. THEN you can use any type of screw you want.:thinker:

Drill holes in the slab that align with the predrilled holes in the threshhold you bought. Install plastic anchors in the holes. THEN you can use any type of screw you want.:thinker:
Yeah, I thought of that....but then I must drill thru 1/4" of tile, and then some concrete.
The best solution would be the smallest possible anchors....would that be plastic or lead.
(probably plastic, right ?)