Very nice! You will not find an acceptable bearing tip for that size of top, you will have to make one. The biggest (and best) you can buy is the S8 tip assembly (can get
here) but it will be too small IMO. Making a bearing tip from scratch is 37 times harder than making a fixed tip from scratch. A top of that size would regenerate well with a fixed tip...
I have some pointers on making a fixed tip on a wood lathe if you are interested.
I have a guess on how thick the string would need to be and could make you one for a few bucks.