To anyone stumbling across this thread like i did looking for a cactus farm, but with fences viable for vanilla, i have made a module easy for autobuild to build.
Information:
The module is 15x15 containing 8x8 cactus, it uses string so you do not have to break anyblock for it to be placed, it does use alot of string. It is easy to stack, and i myself have made one on a server myself. It is made out of cobble so it is easy to build and oak fences since made on 1.8
How to build:
If build on a multiplayer server that is lagging or just under 20 tps in general use "Check line of sight" so that the sand does not get missplaced due to ghostblocks or lag. If on a singleplayer world this does not matter, since there is no lag or ghostblocks.
When building on multiplayer start low so that the cobble and string inbetween get placed first, and then u can go place sand, fences the other string and cacti at the same time, it is only important that the cobble gets placed first. If autobuild does something wrong go over to the first placed block and break it together with the sand and place a new cobble stone block, it should fix itself.
Sometimes autobuild makes mistakes and u need to break sand and string over the cobblestone blocks or elsewhere before restarting it.
The farm in the picture i build on a 10 tps server in 3 hours alone.


Sorrry for any misspelings
VIdeo on how to use:
youtu.be/9STKgjGaKjk
Template:
files.fm/u/qwr9t9xyv4