I just sent you an email through Curezone giving you my email address. Look for it. It may show up in your Curezone "inbox". I abide by the rules at Curezone and seldom discuss business on the forums.
I don't think the ASO 250 is strong enough for a steam sauna, but it has been used by a few people as a temporary measure with good results for this purpose when budget was a concern. When these people were able to move up to a better machine they were very happy to do so because the results are definitely superior. I expect the ASO 250 is roughly equivalent to the Synergy Single in terms of ozone output. The Synergy Double or the Coronaire Maxi are much better for the sauna but the real Cadillac is the Oxygen fed HTU 500 from Azco.
The two terms do not relate to each other at all. Mg/hr is a measure of the weight of molecular ozone produced by a machine in one hour. Ug/ml or gamma is a measure of the molecular weight of the ozone in a mixture of ozone and oxygen that takes up 1 ml of volume. It also relates to concentration of ozone. The higher the number of ug in 1 ml, the higher the amount of ozone in the mixture of ozone and oxygen.