I think 6th man Fox would eventually be a nice role for him... but IMO you just can't have 25% of the cap coming off the bench, even if it's still at 30mpg... but maybe I'm just thinking too traditionally/"old fashioned" in that sense. I do agree that Harper is going to be too good to be coming off the bench eventually and will become a max player himself at some point.
I do see people talk about Fox taking a pay cut... but in the NBA contracts cannot be renegotiated downward to help a team's cap... they can only be renegotiated upwards.
I still there there is a chance that Castle can be a playmaking 3 "point forward" that let's all 3 play together, but when they've shared the court so far it has not been good. I think it relies on one of them becoming a good pull up 3 point shooter as
@ambchang stated. I also think the best chance of the 3 of them working together relies on something next to Wemby that we don't currently have, which is another versatile big so you can go 3+2 rather than 3+1+1 (using my Guard/Wing/Big Spurs position classification). Kornet isn't the right guy for that... not to beat a dead horse but Maxime would have been a better fit for that. Maybe Mara?