No problem but it wouldn't show anything since it is small and inside the air hole so nothing really to see from the outside. But I will describe it in detail since it will help more.
Take some wire, length about 8 cm approximately.
Wire diameter will choose the reduced hole diameter. I used 0.4 mm(26 awg). Since standard hole is about 2.2mm, minus reducer 2x0.4mm it comes about 1.4 mm. So depending of your preference you choose the wire diameter.
Wrap it tightly around 1.5 mm rod (or different if you want different air hole diameter) to come about 5-8 mm in length (this depends on the tank, used about 8mm for Nautilus RBA).
Cut the reducer so it does not have legs, just rounded part.
Carefully insert it into the air hole by screwing it the same way the reduced is wind. Eg if you wind your reducer clockwise, rotate it in the same direction in order not to get it stuck.
Cut wire if it protrudes out of the air hole using nail clippers or flush wire cutter in order not to have shorts after you install the coil.
This is how I did it. All the credits for this go to
@rew and
@quincey43, I just shared steps I used to perform it.
If your air hole for other tanks are different diameters just calculate it as:
Standard air hole - 2x wire diameter.