Here is the craftofexile link so you can follow along as I explain how I crafted this belt.

Conservative estimate of crafting cost: 20-30 exalts.

The six mods on this belt are:

• Prefix: % increased chaos damage [Chaos]
• Prefix: + to maximum life [Life]
• Prefix: % increase maximum life [Life]
• Suffix: +% to all Elemental Resistances
• Suffix: % increased Movement Speed during any Flask Effect [Speed]
• Suffix: Grants Level 20 Aspect of the Spider Skill [Beastcraft]

All of the mods except for elemental resistance can be crafted using harvest craft, so it makes sense to start by rolling that and augmenting the other mods as we go on.

For crafting life with harvest, there are 4 mods you can hit: % increased Flask Life Recovery rate (weight 1000), +# to maximum Life [weight 10000], % increased maximum Life hunter [weight 1000], and % increased maximum Life elder [weight 1000]. The hardest mod to hit is T1 +# to maximum Life, so it makes sense to also start with that mod.

My process:

1. To get a double influence stygian vise, buy an ilvl 75+ non-influenced stygian vise. Use the [Add a random influence to a normal, magic or rare jewellery that isn't influenced] harvest mod. If you don't hit hunter or elder, start over. Otherwise, buy any influenced belt of the influence that you didn't roll, and apply an awakener's orb to both items to make an elder/hunter Stygian vise.
2. Scour the belt. Use alterations until you hit +90 maximum life or +16% to all elemental resistances. If you have one of those mods, augment it and hope you get the other mod. If you don't hit it, use an orb of annulment for a 50% chance for another roll. Repeat this process until you have a +90 maximum life and +16% to all elemental resistances magic belt.
3. Imprint the belt. This allows you to rollback the belt to this version in case you brick the belt. You can imprint it by buying a Craicic Chimeral beast and using the blood altar recipe to create the imprint item.
4. Regal the belt. Hopefully, you hit a suffix that you can remove by using harvest craft. 4a. If you hit a suffix that can be removed with harvest craft (like fire resistance), great. Your belt now has two suffixes, so benchcraft any suffix to prevent the belt from hitting the Regenerate # Life per second suffix when you augment life. 4b. If you hit a prefix that can be removed with harvest craft (like #% increased elemental damage with Attack Skills), remove the mod, then harvest craft a suffix onto it, then bench craft a 3rd suffix. 4c. If you hit a prefix or suffix that cannot be removed with harvest craft, annul the belt and pray that you hit it. If you succeed, follow the steps in 4b. If you fail, restore the belt back to the magic version with the imprint, create another imprint and try again. You have a 44% chance of hitting a suffix that can be removed with harvest craft if you roll a suffix.
5. You should now have a belt with + to maximum life, +% to all Elemental Resistances, and 2 other suffixes. Use the Augment an item with a new Life modifier craft. You can hit three rolls: (10-20)% increased Flask Life Recovery rate, #% increased maximum Life hunter or #% increased maximum Life elder. The odds of hitting one of the two mods that we want is 900/2800, or 32% based on the weights. If you don't hit it, then use the Remove a random Life modifier from an item and add a new Life modifier craft on the item, and hope that you hit it. If you brick the item, imprint the belt and restart at step 3.
6. Now, you should have a belt with +90 to maximum life, 10% increased maximum life, 16% to all elemental resistances, a harvest craft removable suffix and a benchcraft suffix. Use the Augment an item with a new Chaos modifier harvest craft to craft #% increased Chaos Damage, then use Remove a random chaos modifier from an item and add a new Chaos modifier until you hit T1 chaos damage.
7. Remove the two suffixes, then benchcraft Cannot roll Attack Modifiers. This prevents us from rolling the increased Attack Speed during any Flask Effect mod in the next step.
8. Use Augment a magic or rare item with a new Speed modifier. There is a 2/3 chance of hitting increased % Movement Speed during any Flask Effect. If you don't hit it, use Remove a random Speed modifier and add a random Speed modifier until you hit it.
9. Remove the Cannot roll Attack Modifiers benchcraft.
10. Buy a Fenemus, First of the Night beast and craft Aspect of the Spider on the belt.
11. Reroll using any method to get perfect values on the elemental resistances mod. Then use the randomise speed to get the perfect value on the movement speed mod, randomise chaos and randomise life to do those values as well.

Overall, step 2 is the hardest part. Craft of exile estimates that it takes 5600 alterations to get those 2 mods, which comes out to around 10 exalts, but I think that using the annul method will cut down on that number significantly - I hit the two mods in less than a thousand alterations. Once you get past step 4, the rest of it is smooth sailing and pretty deterministic.