I have heard of major discharges from the ears after several auricular insufflations, but I've not heard of blood from sinuses. The ears, nose and throat are all connected so anything is possible. It may be a cleansing reaction as you suspect.I would expect that the tightness in the chest is a result of breathing too much of the raw ozone while doing the treatment.
There is no reason why you could not block off the unused side of the steth if you wish to do one ear only. Your assumption is correct that the active ear would receive a higher concentration.
As far as your machine is concerned, most water ozonators are specified at mg/hr. This is a measurement of the molecular weight of ozone produced per hour irregardless of air/oxygen flow rate through the machine. To know the exact concentration it is producing would require knowledge of the amount of air flow the internal air pump is pumping. 400 mg/hr is approximately as follows in gamma or mcg/ml if the machine were used with pure oxygen. Mcg/ml is a measurement of the molecular weight of ozone in a mixture of oxygen and ozone, and this is how medical grade ozonators are specified.
1 lpm oxygen flow- 8 ug/ml
1/2 lpm oxygen flow-15 ug/ml
1/4 lpm oxygen flow-25 ug/ml
1/8 lpm oxygen flow- 38 ug/ml
1/16 lpm oxygen flow-45 ug/ml
1/32 lpm oxygen flow-61 ug/ml
If you can find the specs of the pump in your machine, you can determine it's output concentration. Bear in mind though that using room air for ozone generation will lessen these figures.
hope this helps clarify