Okay, that's good, also, I came to my attention that the Image spell is replaced? That's not good because I replaced Image myself for one of Baigan's Arts.
Hmm... I think I miswrote there, Sky Rave replaces Pin rather than Image. Still the same case, if you wanted to change that to a different spell slot (Sight, perhaps?) than you could do that by changing
$03/EA53 C9 9F CMP #$9F A:0501 X:05B0 Y:BDB2 P:eNvMxdIzc - Is it Red Dragon?
$03/EA55 D0 04 BNE $04 [$EA5B] A:0501 X:05B0 Y:BDB2 P:eNvMxdIzc - If not, jump to next Dragon Check.
$03/EA57 A9 46 LDA #$46 A:0501 X:05B0 Y:BDB2 P:eNvMxdIzc - Load Sky Rave into A.
$03/EA59 80 25 BRA $25 [$EA80] A:0501 X:05B0 Y:BDB2 P:eNvMxdIzc - Branch to Spell Finding Routine.
And taking...
$03/EA57 A9 46 LDA #$46 A:0501 X:05B0 Y:BDB2 P:eNvMxdIzc - Load Sky Rave into A.
And changing that to...
$03/EA57 A9 46 LDA #$17 A:0501 X:05B0 Y:BDB2 P:eNvMxdIzc - Load Sight into A.
To find this in ROM just crack open a hex editor and search for C99FD004A946 and changing the 46 at the end there to 17 and you should then free up Pin's slot again.