Replicator+ Experimental Extruder Filament Slipping Error
As the comment section doesn't allow to use too many characters, I've converted the comment into a proper answer.

In the question is stated that: 


  ... results of testing the Experimental Extruder with a larger nozzle
  often required a lower extrusion temperature...


This is in contradiction with expectations. When the filament feed rate or volume increases, generally a higher temperature is required to heat up the filament because the resident time of the filament in the heatbreak and nozzle decreases. 

As the filament heat up time is shortened by the increased feed rate you should either:


increase the temperature to get the filament center to also heat up. In fact, all your problems could be related to not heating up the filament too fast (filament jam or slip). When the center of the filament is not soft enough, it will be harder to push through the nozzle, hence the slip and the clogging, or
decrease the print speed, decreasing the print speed will increase the filament resident time.


As an example, a nozzle/layer height combo of respectively 0.4/0.3 lays down 4 mm³ per 100 mm, a 0.8/0.6 combo delivers about 30 mm³ for that same distance! This is a lot of heat that is dissipated and needs to be replenished. A reduction of print speed by a factor of 7.5 (30/4) will also address the increase in heat up time.