Fluid pessure in branched closed pipe system

Hi all!

I have a question. If I have the following system would I experience any pressure difference at the two manometer if I change the openings on the velves? Basically I would like to split (roughly equally) the flowing fluidum (water) between the two device without using a flowmeter. My assumption is if the two manometer show rougly the same pressure then the flow rates are (rougly) equal.

Please tell me how wrong am I? :D