How do I calculate Item level to help me when I shop in Hellfire/Diablo?

In the Jarulf’s Guide to Diablo and Hellfire

it states (in the table '' Definition of ilvl for Griswold’s premium items'')

At Griswold the 14th slot will be: clvl + 3

And since I'm lvl 13: the ilvl can go up to 16 in that slot

For a King's Bastard Sword of speed (same attack speed as haste) I don't know how to calculate the ilvl (qlvl) can someone help me? Same thing for the Jester's Sword of the leech.

Because I'd like to know the optimal level to farm this item, I've read that a King's Bastard Sword of haste is ilvl 28 but it is quite complicated to calculate this, if I had one example perhaps I could understand better.

The best level to farm is 1 level lower than the ilvl or the same level. because in Hellfire there is 4 slots with +1 ilvl and 4 slots with the same ilvl (Griswold).

For Griswold it's as shown on the table here:

Let's say you are level 11 in Hellfire for Premium items Griswold will have

• 3 slots will be ilvl up to 10
• 4 slots will be ilvl up to 11
• 4 slots will be ilvl up to 12
• 2 slots will be ilvl up to 13
• 2 slots will be ilvl up to 14

For the base quality (Bastard Sword, Scimitar, Broad sword etc.):

the range is the ilvl/4 to the ilvl of the slot

so in the first 3 slots it will be 2.5-10 (for numbers with decimals it will be rounded down) so 2-10

For the prefixes and suffixes: it is ilvl/2 to the ilvl of the slot

so for the first 3 slots if will be 5-10

So For a Jester's (qlvl 7) Sword (Bastard (qlvl 10) of the leech or bat (qlvl 8)

level 11 or 12 is the best levels to find the sword type (qlvl 10). Because in the lowest slots you can get the sword type and in the highest slot you can also get the lowest modifier (qlvl 7).

sidenotes

In Hellfire Griswold will try to always sell you items that are at least 80% of the value you carry, so get 1 type of each item with a very high price and get (in this example a sword) the item type you need to be just lower it's value (with the 80% idealy so a more expensive one is better), the sword I was looking for was around 17k so having all the other types of items with value over 20k (with the 80% in mind it is better to have very expensive ones so he won't be able to generate any of that type for the ilvl he's allowed to sell, sometimes it fails on some slots) and having a sword of 14k made it a lot easier. (in MP there's no jewelry sold by Griswold) So Griswold did propose me lots of swords and around the value I needed and finally got one.

ilvl=item level

qlvl=quality lvl

The highest prefix/suffix or base qlvl is what matters for the determination of what will appear/what's possible. Max qlvl 30 for Griswold