On the subject of do they work or not. Yes they make a big difference. I DIY'ed some and also made one for the rear stabs. The fronts take out 70% of the wiggle and the rear takes the rest out. When on blacktop it's as solid as can be, when on dirt or gravel we get some movement. Not much but some. It's really hard to get the rear jacks tight with dirt or gravel under them. What I found was to get the front of the 5'er near where you want it to be, lower the rear stabs and snug them up good. Then raise the front to where you like it. That puts a little more pressure on the rears.
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