Chart for looting a library

[J-H]

My players will eventually hit a "Room of Lesser Magics" (spell levels 0-3) in a library. I don't expect them to spend too long searching it, but I want to reward "longer" searches (costs them time = prep time for enemies, etc.).

I want to use some combination of Investigation and Arcana checks where they find more if the roll higher on both, and where they also find more items if they take more time.
Nobody's used a single scroll the whole campaign so I'm not too worried about loading them down with 6 low-level scrolls of random utility-ish spells. I just don't know how to chart or relate the two checks and the investment of time. Suggestions?

[Laserlight]

What are the minimum and maximum number of scrolls you want them to find? Once you have those parameters, you should be able to work it out fairly easily

[J-H]

I don't really have a specific number in mind.

I'm not sure what else in terms of game-useful items would be in a library like that.

[Lunali]

Mundane items: maps, cartography kit, components of a forgery kit, paper, ink, quills, magnifying lens (which is probably expensive given the cost of a spyglass), books with information relevant to the party

Magical items: light source, translator, copying, seeking, etc. Some or all might only work in the library.

[Laserlight]

Silent kettle, spillproof tea cup, and a cat.

[Lunali]

Silent kettle, spillproof tea cup, and a cat.

An ordinary cat that knows exactly where everything is, but won't lift a paw to help find it, will instead sit judging you as you search.

[J-H]

The gynosphinx is already two rooms over :)

[J-H]

Ok, I figured it out today.

Score: Investigation + Arcana + 5x hours invested
21 investigation + 22 arcana + 1 hour (5 points) = 48
21 investigation + 22 arcana + 5 hours (25 points) = 68
I guess I should have them roll by hour.

Library of Lesser Magic
Score Item(s)
25 Cartography kit
30 Scroll of Elemental Weapon; Instrument of Scribing (XGTE, A)
35 Components for scribing spells into a spellbook, Scroll of Dragon’s Breath
40 Scroll of Tidal Wave
45 Scroll of Bane; Scroll of Arcane Lock
50 Scroll of Vampiric Touch
55 Scroll of Unseen Servant
60 Wand of Secrets
65 Scroll of Beast Bond; Scroll of Arcanist’s Magic Aura
70 Scroll of Longstrider
75 Scroll of Flame Arrows
80 Scroll of Web

Room of Greater Magic:
Score Item(s)
25 Scroll of Immolation
30 Scroll of Transport Via Plants
35 Scroll of Reverse Gravity
40 Scroll of Contagion
45 Figurine of Wondrous Power (Silver Raven)
50 Scroll of Seeming
55 Gem of Seeing
60 Scroll of Staggering Smite
65 Pearl of Power
70 Scroll of Dominate Beast
75 Tome of Clear Thought
80 Scroll of Divine Word
85 Scroll of Delayed Blast Fireball
90 Manual of Quickness of Action


There are time pressures, so I think they only have a moderate chance of actually getting either of the tomes. The tomes also require more time than the campaign allows to easily read through.