A
Taco VR1816 won't break the bank, and offers many more tweaking options. It's about $100 more than the dumbest low efficiency 007s, ~$70 more than an
007e. (Gayewski won't like it, but he's neither paying your power bill nor fully designing your system.) In fixed-speed mode the VR1816 behaves roughly like the 003 when set to minimum speed, but roughly like the 0015 when set to maximum speed, with a whole lot of other stuff in between. But in most systems using on modes other than fixed speed will be more optimal.
In a well designed system the pump would be running a VERY high duty cycle, and a dumb 007 or 0015 would be chewing through a lot of power to no good end. If you have 5 cent electricity that might be no BFD, but in my area residential retail electricity has edged north of 25 cents/kwh, and annual circulator power use has become QUITE relevant for radiant heating systems. Like mileage, your electricity price may vary.
As a general observation, design by web forum is not the best approach to fully optimizing the system. At best it can (hopefully) steer you away from expensive disaster designs requiring major re-work and component swaps to get it do deliver what you want. And even the best designs can be thwarted by incompetent installation. Hydronic heating is
not a mere "plug-and-play" exercise in plumbing, hooking up the right ga-z
intas into the right ga-z
outas. (Sorry if that antique TV reference is too obscure.
)