Tome of Furion, can I roll first and then pick a spell?

[Forumite]

Initially I thought the wording of the item was that you first pick one spell for the Tome of Furion, then roll any remaining spells the usual way. Rereading it, I´m not sure I have to pick the ToF spell first. Can I roll my random spells and THEN pick a spell that I failed to get by rolling? That should greatly increase the chance of getting the right combination of spells, at least for a lvl 4.

[Dalamar]

You pick your spells during spell selection step. The item doesn't specify when.
Mathematically it makes no difference, the only difference is in perception
Pick before or after you roll the other spells, whichever you prefer as long as you pick the spell before rolling spells for another wizard.

[Calisson]

If you want absolutely one spell, or one specific pair of spells, it makes absolutely no difference indeed as far as probabilities are concerned - but it does as far as psychology is involved.
Only if you would be happy with either spells A and B, or C and D, then it would increase your chances to pick up after rolling.

Recommendation: if you are not in the last case, don't start the game with an unnecessary argument.

[Daeron]

The order matters not when aiming for a specific spell, or a specific combination. The order matters little when needing one of two combos.

The order matters when you take into account spells you do not want. Say, you don't want spells 1 and 2, because they are ineffective against this enemy but you don't mind swapping out one for Doombolt. Then Tome of Furion can help out if you rolled both of them.
My napkin math points at 1/18 chance (or 5.5%) on getting spells 1 and 2 if you used Tome of Furion first.

It may not be worth an argument at the start of a game, but I don't see why an opponent would want to make a deal from it either.

[Forumite]

Of course, why didn´t I see this? I´m supposed to be good with numbers. Thanks for the explanation.