Bubbles are prob just from emulsions. Shaking things up a bit gets lots of air bubbles down in the basic solution and caught up in the bark, and letting things settle will free the air up. That will cause you no problems at all my friend, and you have used plenty of water. a quarter of that is what swim would use, and swim has done lots of experimenting with water/lye/bark ratios in the past before he learned about lime. As long as its a black liquid you're good to pull away with that NP.
Most people use radically too much water and or lye when doing extractions. Reducing the lye is environmentally, rationally, and economically smart. Reducing the amount of water used theoretically should boost yields to an extent. This is due to FB DMT and FB DMT-N-Oxide being slightly water soluble.
Also in Swim's opinion, smaller base volumes are easier to work with and less is spilled in the event of catastrophe.
SWIM does think there is a point where you can get too little water, but if you stay at 1 part bark 1 part lye 4 parts water by weight you will be good.
Water is 1g per ml.
Keep it simple and you will be rewarded.
Cheers-