I have had a number of private messages and emails regarding the Robust and other aftermarket toolrests for the G0766 lathe. Thought it would be prudent to place some information here for viewers as a reference on the matter.
#1 - banjo hole- I recommend highly that all G0766 owners bore out the 25mm hole to 1"....a difference of .004" and can easily be done using a twist drill bit and some oil to lubricate the cut. This will allow for many standard issue aftermarket accessories to be used, like coring rigs, threading jigs and others that come standard with 1" posts.
#2 - As related to Robust rests for the G0766 - I got mine custom made to 8.75" total height [from bottom of post to top rail, where the tool actually touches the rest] but I have heard that there is plenty of post in the newer banjo to allow a 8.5" post, total height, but I have not personally verified that. That being said, Robust can make 25mm posts, but if you keep the 25mm hole, you limit the other accessories as I mentioned above, and it is such an easy modification that I don't know why anyone would not want to do it.
#3 - Other make tool rests [like round bar rests] can also be used, not just the Robust......just make sure total height is 8.5 to 8.75 inches, top to bottom.
#4- I also had a question or two about banjo replacement - If you got a G0766 after about September 2015, then you likely have the updated banjo. Some were thinking they needed to replace that and wanted to know which Oneway banjo to get.........with the updated banjo there is no need for a Oneway. Although I did get the Oneway because I was not willing to wait on Grizzly's upgrade, I now use the updated banjo from Grizzly exclusively. I am happy with it. If you are not sure you have the updated banjo, just measure the base........if it is 17" long at the base, you have the updated version. Replacements were shipped by Grizzly to all the owners who previously had the smaller banjo along with the appropriate hardware to make the conversion.
Hope this information helps all those who are considering aftermarket rests for your G0766.