This is exactly what I do. Almost everything has a nice DHCPv6 address so that I can actually remember the ULA + the suffix, but then for the two devices on my network that don't do DHCPv6 they get a SLAAC. One oddity though is that it means most devices on my network have both a SLAAC and a DHCP-provided one, since I wasn't able to be able to get it to prioritize a DHCP. Combine that with them having both ULA addresses and public addresses and some stuff on my network have way more addresses than you'd expect