I need advice on maximising my lvl 104 Samurai's SP while still retaining ATK, DEF and, if possible, MOVE and JUMP.

Right now she has:
Amano - Hahakiri
Lv 0
SP 400
ATK 1252
INT 400
SPD 74
HIT 69

Royal Ring
Lv 0
HP 300
SP 150
ATK 150
DEF 219
INT 150
SPD 224
HIT 150
RES 150

Muscle World (Otherwise I found she had too little HP)
Lv 0
HP 1085
DEF 35

Falcon Shoes (Extra MV and JUMP are nice)
Lv 0
DEF 31
SPD 167

Keep in mind I have limited resources, especially in the way of orbs (which are all on my cleric and galaxy skull).

Any help is appreciated.

Well, to avoid compromising anything else, you'd likely need to either:

A - Level her up a lot...With level ups, comes extra SP...

B - Farm "Master" specialists....They boost SP, and once you've subdued them, you can move them to whatever item you want...

Why do you need so much? Do you plan to go through 10 levels of the item world killing everything with high level skills or something?

Etna mode is hard when you're fighting enemies twice your level and only have enough SP for 5 nightsevers. (and don't have the time to level up sufficiently)

Ahhh, I see....Well, thats why I still haven't gotten around to Etna Mode, enemies are just too damned high leveled (unless you've trained a lot in CoO3 in regular mode)...

Just....I dunno...Level farm in the areas that you can beat enemies...Perhaps weaken a bunch of monsters, combine them into one high level, but weakened monster, and kill them with the character you want to level....

Oh, if you don't mind doing a sort of glitch exploit, try grabbing Foresight (I think thats them) glasses from the shop...you'll see that some of them contain subdued specialists...These boost EXP, Money, Mana, and Weapon Mastery gains significantly...Only if you don't mind using this glitch...

Haha, Etna mode's not that bad (unlimited horse weiners ftw)- I went straight into it from my firt playthrough, with lv 70s, and i've only had trouble with 2 or 3 stages to date.

But back on topic, i'll try grabbing Foresight (I think I might already have it).

NOTE: It is only the Foresights bought in store (so you need to have product rank around 8 or something), and only some of them...

Don't see any glitched subdued specialists? Exit the store, and go back in...

You want:

Statician - Raises EXP gains to max (300% boost)
Armmaster - Boosts Weapon mastery leveling (300% boost)
Broker - Boosts HL gains from killing enemies (300% boost)
Manager - Boosts Mana gains from killing enemies (300% boost)

All are very useful, though high level weapon mastery = more SP spent on the skills....But Staticians more than balance that out....Broker allows you to get the expensive items a lot earlier than usual, and Manger ditto for creating high tier (and Genius rank) characters....

How many hours have you been playing
this game to get to lvl 104? I've been playing for 32 hours and Laharl
is only at lvl 14. What strategy do you use to lvl up?

Just complete the game first. Well, get to about the end of the game, then unlock the CoO. Which is the Cave of Ordeals >.>

The second stage of these maps helps a lot in gaining exp. Easily with a winged slayer on a powerful character can be an instant lv 200.

By unlock CoO do you just mean defeat all the demons or is there some hidden "thing" you have to do?

Pass the bill in the dark assembly. But of course, the senators are bastards and don't want you to pass it >.>

if you are looking for orbs try to capture the enemies on
Stellar Graveyard - cross point
each one carries at least three orbs some moon, star, and king, and you get rare and legendary ones.

this also helps to gain Hl just make sure that you unequip all there items then dlete the captured enemies before you heal the team.

for leveling up i found that the two good areas are
stellar graveyard - valpulgis
Celestia - field of virtue

on the first if you have an attack that covers an area of 3x3 then you can get them all in one attack. the second area has EXP +100%. these enemies will be great for leveling up your level 104 character.

the CoO routine of area three is little harder because enemies are level 150 and have high defense so get your guy up there before attacking. they are also in a 3x3 formation.