How to calculate give item damage value for custom models

Diamond Hoe = damage 1561

Move comma two places to get percent (the number on the left is the number you will use in your JSON file)
0.10 = 10%

get percentage of damage value
1561 / 10 % = 156.1

Drop everything after the comma value and add 1
156 + 1 = 157

use answer as damage value in give or summon command
/give @p minecraft:diamond_hoe 1 157 {Unbreakable:1}

Remember to summon item with the unbreakable tag else the first time the item is used it will get damaged and will be replaced by next model.

EXAMPLES
Percent = damage value in texture file [summon / give damage value]
1% = 0.01 [16]
1.1% = 0.011 [18]
1.2% = 0.012 [19]
1.3% = 0.013 [21]
1.4% = 0.014 [22]
1.5% = 0.015 [21]
10% = 0.1 [157]
10.1% = 0.101 [158]
12% = 0.12 [188]
12.1% = 0.121 [189]
20% = 0.2 [313]
20.1% = 0.201 [314]
30% = 0.3 [469]
31% = 0.31 [484]
40% = 0.4 [625]
40.1% - 0.401 [626]
40.2% = 0.402 [628]
40.3% = 0.403 [630]
40.4% = 0.404 [631]
40.5% = 0.405 [633]
40.6% = 0.406 [634]
40.7% = 0.407 [636]
40.8% = 0.408 [637]
40.9% = 0.409 [639]
41% = 0.41 [641]
41.1% = 0.411 [642]
41.2% = 0.412 [644]
41.3% = 0.413 [645]
41.4% = 0.414 [647]
41.5% = 0.415 [648]
41.6% = 0.416 [651]
41.7% = 0.417 [650]
41.8% = 0.418 [653]
41.9% = 0.419 [655]
42% = 0.42 [650]


LionS = 16
LionW = 18
RhinoS = 19
RhinoW = 21
GiraffeS = 157
GiraffeW = 158
PangolinS = 188
PangolinW =  189
VultureS = 313
VultureF = 314
ElephantS = 469
ElephantW = 484
Baloon = 625
Jeep = 626
Camera = 628
RhinoHorn = 630
ElephantTusk = 631
villageman =  633
Night Vision Goggles = 634
Binoculars = 636
Turtle = 637
TurtleW = 639
Hippo1 = 641
Hippo2 = 642
exclaimationmark = 644
Prisoner = 645
GPS = 648
VuVuZela = 647
Hyena walking = 650
Hyena standing = 651
Porcpine Walking = 653
Porcupine standing = 655

scoreboard players set @a nightvision 4 {Inventory:[{id:"minecraft:diamond_hoe",Slot:-106b,Damage:634s}]}

/give @p minecraft:diamond_hoe 1 634 {Unbreakable:1,display:{Name:"Night Vision Goggles"}}
/give @p minecraft:diamond_hoe 1 636 {Unbreakable:1,display:{Name:"Binoculars"}}

------ code below thanks to samasaurus6 ------
https://www.youtube.com/watch?v=n1_l5hhU14w

{
    "parent": "item/handheld",
    "textures": {
        "layer0": "items/wood_sword"
    },
        "overrides": [
                { "predicate": { "damaged": 1, "damage": 0.01}, "model": "item/wooden_sword1"},
                { "predicate": { "damaged": 1, "damage": 0.011}, "model": "item/wooden_sword2"},
                { "predicate": { "damaged": 1, "damage": 0.1}, "model": "item/wooden_sword3"}
        ]
}