New Hyperconverged Setup

I am about to setup a new hyperconverged setup with the following

3 host setup
2 x nvme 240gb hd for OS on each host (raid)
3 x nvme 7 tb hd for vm storage on each host (no raid card)
500gb RAM per each host

I am confused during the gluster setup portion using the web ui setup wizard. When asked for the LV size do I input the maximum size of the hard drive on a single host or do I combine the total capacity of the matching hard drives on all 3 host? Example that I would be putting in is hard drive: /dev/nvme1p1 capacity 7tb or should it be 21tb (combined capacity of the matching single HD on the other host). Or is there a better method you recommend? And since I am using nvme hard drive would you recommend using dedup and compression or no?

Thanks