I've mixed it 1% (that's 2g/200cc) but the latest batch is 2% (4g/200cc) - still using it.
I've mixed it stronger since paper dev is ID-62, phenidone based besides the film one (I'm doing some tests with FX-37), so it will last longer.
I mix benzotriazole 2% with alcohol, too.
Try to get the most concentrated alcohol possible.

BTW today I will mix more ID-62.

Jorge O