Crash into Wipe Tower multi-color print with mk3 NO MMU - 1 extruder technique  

Crash into Wipe Tower multi-color print with mk3 NO MMU - 1 extruder technique

Hi Guys - curious if you can guide me in correcting this or provide another method / approach to achieving multi-color prints using an inlay technique. 

(Note that I calibrated my first layer perfectly - and my z-axis is fine when working with normal single color print projects. I am on the latest firmware and slicer software as well.)

I want to start exploring more advanced printing with multiple colors - I found this article:

https://medium.com/@damien.martin.guillerez/multi-filament-print-with-a-single-extruder-using-prusaslicer-2e0746348cdd

..it was really simple to follow, it shows me how to configure the Prusa Slicer to work with 2 models and switch filaments. I want to basically want to perform a text inlay in the main model.  I followed the procedures and it works for the most part as you can see in the video of the test print,  but you will hear the nozzle at one point sound like it is grinding on the PEI texture bed when moving over to the wipe tower. Inspection of the sheet however does not show any damage thank goodness (unless that noise is something else?). Anyway - after a few filament changes - the wipe tower starts to grow and the head eventually hits the upper layers of one point - causing a crash. I cleared the crash and popped of the wipe tower an everything continued.

Video of what you can see / hear:  

BUT - this is only a test print, the real print may be 3 - 5 hours. I know during that time I may have to perform a few filament changes in between - but I'd rather not have to deal with any crashing - so I just aborted the print for now - and have hopes there may be something in my configuration that is wrong.

I am open to other suggestions - such as printing voids / holes and manually filling them with the letters - but this never seems to work right when I do it - the letters are either 2 big or small etc. , so any other ideas on how to achieve an inlay with 2 color filaments are appreciated.

Such as is there a way to use this technique WITHOUT the wipe tower? 

Thanks