Metamagic Feats Question

[Crexis]

Lets say I want to use a level 3 spell Fireball at level 10 (10d6 dmg).

If I have the feats empower and maximize spell.

It says empower takes up +2 slots higher then the spells actual level.

It says maximize spell takes up +3 spells higher then the actual spell.

If I were to use both these feats in conjunction with fireball, I believe it does 60 dmg * 1.5 = 90 dmg total

2 questions:

What level and how many spell slots does using this take up? Total is +5 levels but I'm unsure how it works for which slots it uses up.

Is there better feats/spells to use at that level which will do more damage?

[UnArcaneElection]

You increase the spell level by the indicated values, not the number of slots used. So, if you don't have anything that reduces Metamagic cost and/or pays some of it for you, Fireball with Empower and Maximize applied uses up an 8th level spell slot, although it is still a 3rd level spell for the purpose of computing Save DC and limitations against it going through something like a Globe of Invulnerability.

[Crexis]

At level 10, you don't have access to 8th level spells so I guess you couldn't use it until you gained much more levels?

1 additional question:

I was thinking of taking the magical lineage trait. Any recommendations as to which spell I should use for it?

I was thinking possibly haste or a blaster spell, or some battlefield control spell which will be getting a lot of use.

[Gallant Armor]

Magical Lineage works well with Intensify Spell and Snowball or Shocking Grasp.

Also, you can use a Maximize metamagic rod with an Empowered Fireball prepared in a level 5 spell slot.

When you combine Maximize and Empower you apply them separately:

60 +((10d6)/2)

[Linea Lirondottir]

Note: As I understand it, combining maximize and empower doesn't work that way. They both independently modify the original spell. Maximize will give you 60 points of damage, yes... but empower will only give you +5d6 damage, not +30.

Note: You actually can combine both of those by level 10. You'll need to use a fifth level spellslot and a maximize metamagic rod, though, so it'd be rather expensive.