I have considered all those options and have used it to top off. I have also mixed a full oaked bottle with a full un-oaked bottle and still came up with too much oak. It’s my mistake for following directions on the packaging. I should have started with one spiral. I still would like to experiment with a gallon of wine with the egg white treatment. If I do, will I need to use a bung and airlock or can I use the screw cap. It’s a heavy duty plastic cap with a three dimensional liner within it.
If the wine is bone dry, you should be able to use a screw cap.
Oak is a dangerous thing -- it's easy to over-do it, and while it will reduce with time, that can be a very long time. I was using 1-1/2 to 2 oz cubes per 19 liters, but have reduced that to 1 oz for reds. I view oak as a seasoning, not a flavoring.
I've noted an increasing number of commercial wineries that note on the label that a wine may contain only 25% oaked wine. Considering they are probably using 225+ liter barrels, which have a very low internal surface area to volume ratio, unlike much smaller barrels, so some wineries are going for low level oak flavoring.