And yes, you can use both the SD2Vita and the original memory card at the same time, but the second card can generally only be used for Adrenaline and emulators. You can't install Vita games to both, they can only be installed to the ux0 partition so if you wanted to use both for Vita games, then you'd have to keep swapping mount points whenever you wanted to play a game on either one of the cards.
.

You can't install Adrenaline itself to uma0, but PSP/PS1 ISOs and homebrew can be put on uma0. Just open Adrenaline settings, and change Memory Stick Location to uma0. This will put a pspemu folder in uma0, which you can then put all your PSP/PS1 games and such into.Can i ask how to install adrenaline to the memory card?
Ive installed adrenaline and its installed itself to the ux0 (sdcard) along with the psp firmware.
Should i just move the directory to uma0?