The original purge bucket was a revelation. It sped up my prints and reduced wastage when doing two-color prints.
This version is a curved chute with a side exit. You need to put a layer of foil tape on the inner surface. With the tape, PLA slides right through the chute. The bucket doesn't reach to the edge of the aluminum extrusion because it would hit the Z-axis end-stop. Instead, I put another flap of aluminum tape to guide purged filament into a tray next to the printer.
For a wiper, I double up two layers of 1mm silicone sheeting (find it on Amazon). Alternatively, pick up some 2mm sheet (https://www.amazon.com/Silicone-Durometer-Smooth-Backing-Thickness/dp/B00LNE8CZW/ref=sr_1_5?s=industrial&ie=UTF8&qid=1549075387&sr=1-5&keywords=2mm+silicone+sheet)
I took 3DMN's G-code for S3D and adapted it for use in Cura. Here's the current iteration.
Settings > Printer > Manage Printer > Machine Settings > Extruder (1,2) Tabs. Paste the following in the extruder start/end G-code for EACH extruder.
EXTRUDER START G-CODE
; Start Extruder 1
M211 S0 ; Turn off soft stops
G1 X-9.5 F6000 ; Go to X=-9.5 at 100 mm/sec
G92 E0 ; Reset extrusion distance on new tool
G1 E50 F90 ; Extrude 50 mm of filament at 1.5 mm/s on new tool
G92 E0 ; Set current extruder position to 0mm
G0 F10000 ; Increase feed rate before next travel.
EXTRUDER END G-CODE
; End Extruder 1
G92 E0 ; Reset extrusion distance
G1 E-5 F5000; Retract 5 mm
G91 ; Switch from absolute positioning to relative positioning
G1 Z1 F1000 ; Lift nozzle by 1 mm in relative positioning mode
G90 ; Return to absolute positioning
G92 E0 ; Reset extrusion distance on old tool
IMPORTANT: Make sure you set the "nozzle switch retraction distance" to 0, or you'll end up with big blobs on your print.