Regular tomatoes have much more liquid than the meaty plums, would it be wise to take out the seeds
salt and drain first?
With all the tomatoes at our Farmer's Market, I have not seen plums. I think they are harder to grow? I tried growing San Marzano a few times with little success, and I recall asking a grower if they had tried San Marzano and she had the same experience. Might just be our hot climate.