Over the years there has been a lot of discussion re incubator temps.
I've know a breeder who incubates everything from woma to spotted at 29.9C and another who vowed and declared that woma would not hatch at a temp less than 31.5C
That person was a keeper of some 25 years experience and he was wrong, at 29.9C they just take a bit longer.
At the other end of the scale the largest breeder in USA incubated everything at 32C
Eggs are made tough,. You mentioned 30.5C, that's fine. Myself I use 31.5C and have done for many years.
Over the years I've played around with incubator temps and used temps as low as 24.5C and had eggs hatch. Admittedly at that temp the incubating time blow out to around 123 days but eggs do hatch.
The most common temps used are anywhere between 30 and 32C so pick a figure you like and all going well the eggs will hatch......