1. Do these types of filters have any common blowby issues?
Not that I'm aware of
2. Are the flow rates good enough to filter 50 barrels in a few hours?
That will depend more on the size of the filter area than the different dosing style, although adding more DE to the dosing tank is slightly more difficult.
3. How easy are they to CIP in comparison to a DE filter with a dosing tank and dosing pump?
Easer if anything.
4. Is filtering under pressure going to be an issue with this style of DE filter?
5. Are there still replacment parts out for these types of filters?
Depends entirely on the unit you have
6. Is there someone running one in the northwest I could come and watch?
That I don't know
Free State Brewing Co.