Added a improvements because first design of E3D holder is very weak.
You can use designed stiffer E3D holder or you can use washer for stiffing first design.
Design is still in development.
New experience is with weak radial fan. I has changed the fans to Sunon axial MX30101v2-A99 for E3D and especially radial blower MF50151VX-A99 this is very iportant for cooling the printing thing.
I had need montage for E3D dual extruder on my FLSUN I3 2017. I had took lembasbrot's carriage and made it some improvements.
In Carriage I had made hole for cable from proximity sensor and holes for hex-nuts.
Made new E3D dual-hotend holder with proximity holt. Holder have to you mount from upper side carriage becase it have better stability.
Important - Have to modification on Z-lift screw and nut. Have to swap the nuts and mount on the top. See the photo.
Sensor distance from the bed is compatible with SN04 and SN08 sensors about distance of 1,6 mm.
Lembasbrot, thank you for inspiring me.
Next used things:
X-Limit Switch: https://www.thingiverse.com/thing:2521758
Standard GT2 belt lock by alex_des: https://www.thingiverse.com/thing:1719926
White PU Steel Core belt lock: https://www.thingiverse.com/thing:2522231
Radial Fan Fang https://www.thingiverse.com/thing:2209349