I tried putting them out about a foot. That helps in raising if they're deployed(farther like you say would be even better). The problem is the attachment point isn't high enough for a single spreader rig, unless you have a short footed mainsail. Raising my attachment point about 5-6' above the spreader, greatly improved the lazy jacks to contain the main. The extra angle you get on the aft line makes all the difference, on a single spreader rig.

I wanted mine to be deployable so I can gather them back to the mast when I'm sailing. While were at it, Craig has the hardest spot installed right now-the upper block attachment.

My lazy jacks has cost about $20 total. I've done them twice. 1/4" nylon, two blocks and thimbles. If I ever get them just right, I may invest in better line. But it wouldn't change performance all that much.