Connecting PEX and my existing Boiler Heating System
Given that you are now running only half as many radiators, you might be able to "re-purpose" the surplus to provide hot water for your staple up radiant floor heating.
An important factor to consider is that maximum floor temperature should never exceed 85 degrees Fahrenheit, so you might need to add a mixing valve and a separate circulator pump. Although, (just thinking out loud) I wonder if you could supply the PEX tubing with "less-hot" water being returned to the boiler. Thereby eliminating the need for a mixing valve and separate circulator pump.