You can get small torque wrenches. I got a cheap one from HF and it's probably accurate within 100ftlbs but it "felt" close enough and I haven't suffered any blowouts yet : )
You could also just use a regular wrench combined with a linear scale and do the math.

What you can do is get regular 9/16" wrench, then borrow your wife's scale, and find a way to attach it to the end of the wrench. Then measure from the center of the bolt when the wrench is on it out to where you attached the scale. Whatever that distance is in inches, divide 12 by it to get the effective ft-lbs and multiply the result by 14 and that is how many pounds you want to register on the scale as you apply a steady pull at right angles to the wrench. E.g. if your wrench's effective length is 6", then 12/6 x 14 = 28lbs. You want to register a steady pull of 28lbs in order to apply 14 ftlbs to the nuts.

A scale like one of these you can hook to the end of your wrench directly or with a bit of string. Go for a scale that is maybe no more than 70# if you have to buy one. Not always but sometimes as the capacity goes up, the precision goes down. Cheap chinese junk would probably work in this case because I'm pretty sure I've tightened up some of those nuts by "feel" without repercussions

Steel bolt and castellated nut (so get yourself a pair of pointed pliers to finesse the pin in : ) I just have pins from Harbor Freight