Maybe somone will come foreward, but I wouldn't hold my breath. More likely you'll get some skeptics who claim L-rods can't possibly work because they never learned to use them.
I don't know much about the Spectra, but it has a program that measures the ground resistance and then probably sets some parameters to produce a signal for that ground type. I will repeat myself, if the device uses a rod that pivots/swivels I don't care how many bells and whistles it has, if you can't use L-rods it's not going ot work for you until you learn.
Many LRL pushers say L-rods are easy to learn. I beg to disagree. Typically the more intelligent a person is, the harder it is to learn. People think they know better than those who have learned. "I'm smarter than THAT guy; I can learn it in a few hours." Then they fail. So I strongly suggest you learn to use the rods before putting down big money. It took me a long time, still struggle with it at times. The person's emotional state is a big factor. Gotta get calmed down. Meditation is the best way--just simply counting to five on inhale, hold for two, then exhale at the count of five. Think of nothing else besides the air going in and out. Practice this twenty minutes a day or even twice a day. Don't expect any results for five weeks. Other techniques involve using a GSR galvanic skin response that measures your skin resistance as a biofeedback tool to help you learn to calm down. This can be done but most people are too lazy to follow it through. Or you can spend a few years and do nothing other than pracice with the L-rods. You might get it, or not. Most people never learn but it is doable. It's so easy to psyche yourself out. Gotta stay out of it, or as I say "Put it in God's hands." People just have to cheat and try to observe what's going on. They just fixate on the process like someone gawking at an accident.
Probably the hardest thing for me was to be able to check a visible target to see if conditions are good or not. Of cousre you want to make the rods cross no matter what. There are many times when the rods won't cross because of interference and damned hard to learn not to force/control the rods. They say to angle the rod tips down and they won't move so easily. Of course then they don't move at all usually because the person is trying to hold them still. Gotta let go of the control. A fine line here. Not as easy as it looks.