XHV uses a modified Heavy algo.
Now Cast works very well with Heavy algo.
On my rigs:
1500Hs on Vega 64,
1430Hs on Vega 56,
890/910Hs on RX580 Gygabite hynix memory
Gandalph the developer, has a twitter account where he gives updates and some tips on tweaking performance or problem solving.
So far so good.