diamond = 1562 uses
iron + iron = 502 uses (251, 251)
60 seconds to smelt in one furnace

iron + stone + stone = 515 uses (251, 132, 132)
iron + stone = 383 uses (251, 132)
stone + stone + stone = 396 uses = (132, 132, 132)
stone + stone = 264 uses (132, 132)
iron = 251 uses (251)

impossible combination:
12 eyes, eyecost 10, booksell 14 = 1680 (560 bookshelves)
12 eyes, eyecost 10, booksell 13 = 1560 (520 bookshelves)
11 eyes, eyecost 10, booksell 14 = 1540 (514 bookshelves)
12 eyes, eyecost 9, booksell 14 = 1512 (504 bookshelves)
12 eyes, eyecost 10, booksell 12 = 1440 (480 bookshelves)
11 eyes, eyecost 10, booksell 13 = 1430 (477 bookshelves)
12 eyes, eyecost 9, booksell 13 = 1404 (468 bookshelves)
10 eyes, eyecost 10, booksell 14 = 1400 (467 bookshelves)

two double libraries (1388):
iron + stone + stone = 515 uses (251, 132, 132)
iron + iron = 502 uses (251, 251):
11 eyes, eyecost 9, booksell 14 = 1386 (462 bookshelves)
12 eyes, eyecost 8, booksell 14 = 1344 (448 bookshelves)
11 eyes, eyecost 10, booksell 12 = 1320 (440 bookshelves)
10 eyes, eyecost 10, booksell 13 = 1300 (434 bookshelves)
12 eyes, eyecost 9, booksell 12 = 1296 (432 bookshelves)
11 eyes, eyecost 9, booksell 13 = 1287 (429 bookshelves)
10 eyes, eyecost 9, booksell 14 = 1260 (420 bookshelves)
9 eyes, eyecost 10, booksell 14 = 1260 (420 bookshelves)
12 eyes, eyecost 8, booksell 13 = 1248 (416 bookshelves)
11 eyes, eyecost 8, booksell 14 = 1232 (411 bookshelves)
10 eyes, eyecost 10, booksell 12 = 1200 (400 bookshelves)

stone + stone + stone = 396 uses = (132, 132, 132):
11 eyes, eyecost 9, booksell 12 = 1188 (396 bookshelves)

one double + one single (1182):
12 eyes, eyecost 7, booksell 14 = 1176 (392 bookshelves)
10 eyes, eyecost 9, booksell 13 = 1170 (390 bookshelves)
9 eyes, eyecost 10, booksell 13 = 1170 (390 bookshelves)
12 eyes, eyecost 8, booksell 12 = 1152 (384 bookshelves)

iron + stone = 383 uses (251, 132):
11 eyes, eyecost 8, booksell 13 = 1144 (382 bookshelves)
9 eyes, eyecost 9, booksell 14 = 1134 (378 bookshelves)
10 eyes, eyecost 8, booksell 14 = 1120 (374 bookshelves)
8 eyes, eyecost 10, booksell 14 = 1120 (374 bookshelves)
12 eyes, eyecost 7, booksell 13 = 1092 (364 bookshelves)
10 eyes, eyecost 9, booksell 12 = 1080 (360 bookshelves)
9 eyes, eyecost 10, booksell 12 = 1080 (360 bookshelves)
11 eyes, eyecost 7, booksell 14 = 1078 (360 bookshelves)
11 eyes, eyecost 8, booksell 12 = 1056 (352 bookshelves)
9 eyes, eyecost 9, booksell 13 = 1053 (351 bookshelves)
10 eyes, eyecost 8, booksell 13 = 1040 (347 bookshelves)
8 eyes, eyecost 10, booksell 13 = 1040 (347 bookshelves)
12 eyes, eyecost 7, booksell 12 = 1008 (336 bookshelves)
9 eyes, eyecost 8, booksell 14 = 1008 (336 bookshelves)
8 eyes, eyecost 9, booksell 14 = 1008 (336 bookshelves)
11 eyes, eyecost 7, booksell 13 = 1001 (334 bookshelves)
10 eyes, eyecost 7, booksell 14 = 980 (327 bookshelves)
9 eyes, eyecost 9, booksell 12 = 972 (324 bookshelves)

two single libraries (966):
10 eyes, eyecost 8, booksell 12 = 960 (320 bookshelves)
8 eyes, eyecost 10, booksell 12 = 960 (320 bookshelves)
9 eyes, eyecost 8, booksell 13 = 936 (312 bookshelves)
8 eyes, eyecost 9, booksell 13 = 936 (312 bookshelves)
11 eyes, eyecost 7, booksell 12 = 924 (308 bookshelves)
10 eyes, eyecost 7, booksell 13 = 910 (304 bookshelves)
8 eyes, eyecost 8, booksell 14 = 896 (299 bookshelves)
9 eyes, eyecost 7, booksell 14 = 882 (294 bookshelves)
9 eyes, eyecost 8, booksell 12 = 864 (288 bookshelves)
8 eyes, eyecost 9, booksell 12 = 864 (288 bookshelves)
10 eyes, eyecost 7, booksell 12 = 840 (280 bookshelves)
8 eyes, eyecost 8, booksell 13 = 832 (278 bookshelves)
9 eyes, eyecost 7, booksell 13 = 819 (273 bookshelves)

stone + stone = 264 uses (132, 132):
8 eyes, eyecost 7, booksell 14 = 784 (262 bookshelves)
8 eyes, eyecost 8, booksell 12 = 768 (256 bookshelves)
9 eyes, eyecost 7, booksell 12 = 756 (252 bookshelves)

iron = 251 uses (251):
8 eyes, eyecost 7, booksell 13 = 728 (243 bookshelves)
8 eyes, eyecost 7, booksell 12 = 672 (224 bookshelves)