Rebooting after install lead to, you guessed it, the Black Screen of Death again. Solus was installed, accepting all defaults (and therefore one humongous / paritiion), to /dev/sdb2, /dev/sda1 is the EFI partition on which rEFInd was installed when running OS X MacOS.

❯ lsblk
NAME   MAJ:MIN RM   SIZE RO TYPE MOUNTPOINT
sdb      8:16   0   477G  0 disk 
├─sdb2   8:18   0 473.2G  0 part /
└─sdb1   8:17   0   3.7G  0 part [SWAP]
sdc      8:32   1   3.9G  0 disk 
sda      8:0    0 465.8G  0 disk 
├─sda2   8:2    0   465G  0 part 
├─sda3   8:3    0 619.9M  0 part 
└─sda1   8:1    0   200M  0 part 

#1 Boot back into MacOS, mount EFI paritition:

❯ sudo /Users/yearluk/Downloads/refind-bin-0.10.7/mountesp
❯  cd /Volumes/ESP/loader/entries
❯ nano Solus-lts-4.9.22-17.conf

#2 CHANGE:

title Solus 2017.04.18.0
linux /EFI/com.solus-project/kernel-com.solus-project.lts.4.9.22-17
initrd /EFI/com.solus-project/initrd-com.solus-project.lts.4.9.22-17
options root=PARTUUID=c96bc351-b364-4c61-9fe6-8489f0ceec8f quiet ro splash resume=UUID=8f7d1509-fe95-4e47-8017-41611ad0a14c

TO:

title Solus 2017.04.18.0
linux /EFI/com.solus-project/kernel-com.solus-project.lts.4.9.22-17
initrd /EFI/com.solus-project/initrd-com.solus-project.lts.4.9.22-17
options root=PARTUUID=c96bc351-b364-4c61-9fe6-8489f0ceec8f ro nomodeset nouveau.blacklist=1  resume=UUID=8f7d1509-fe95-4e47-8017-41611ad0a14c text 3

#3 Repeat steps #3 through #8 from Part 1 (#7 this time was modprobe nvidia)

#4 update entire system

sudo eopkg up

#5 using the Apple bootloader [hold opt key whilst booting] to boot… boots graphically now.