Look over the Homebrews version and let me know what is missing from your working draft.
My proposed changes aren't in my Working Draft 'cause you asked me not to update it to avoid confusion, they're in posts 946, 953 and 960.
...told you I was creating new ways to confuse you.
Putting them all together, they are:
Size and Type
The base creature's type remains the same.
Increase the base creature's size according to the following table:
Mystaran Gargantua Size Table
Base Size. . . New Size . Space/Reach (tall) . Space/Reach (long)
Fine to Small . Huge . . . 15 ft./15 ft . . 15 ft./10 ft.
Medium . . . Gargantuan .. 20 ft./20 ft . . 20 ft./15 ft.
Large . . . . Colossal . . 30 ft./30 ft . . 30 ft./20 ft.
Huge . .. . . Colossal . . 40 ft./40 ft . . 40 ft./30 ft.
Gargantuan .. Colossal . . 50 ft./50 ft . . 50 ft./40 ft.
Colossal . .. Colossal .. +30 ft./+30 ft . +30 ft./+20 ft.*
*If the base creature is Colossal, increase its Space by 30 ft. and increase its Reach by 30 ft. (for tall) or 20 ft. (for long).
Hit Dice
If the base creature has 2 or more HD, multiply the base creature's Hit Dice by 8. For mystaran gargantua with fewer than 2 HD, the gargantua will have 12 HD if the base creature has 1 HD and 8 HD if the base creature has less than 1 HD.
Damage
A mystaran gargantua retains all the natural weapons, manufactured weapons and weapon proficiencies of the base creature. The damage values of these attacks increase according to the following table (this includes improvement for increased size).
Mystaran Gargantua Damage
Old Damage . . New Damage by Base Creature's Size
(Each) . . . . Fine . . Diminutive . . Tiny or larger
. 0 . . .. . . 1d8* . . . 1d6* . . . .. . . 1d4*
. 1 . . . . . 1d10 . .. . 1d8 . . . . . . . 1d6
.1d2. . . . . 1d12 . . . 1d10 . . . . . . . 1d8
.1d3 . . . . . 3d6. . . . 2d8 . . . . . . . 2d6
.1d4 . . . . . 3d8. . . . 3d6 . . . . . . . 3d6
.1d6 . . . . . 4d8. . . . 4d6 . . . . . . . 4d6
.1d8 . . . . . 4d8. . . . 4d8 . . . . . . . 4d8
.1d10 . . . . 4d10 . . . 4d10 . . . .. . . 4d10
.1d12 . . . . 4d12 . . . 4d12 . . . .. . . 4d12
.2d6 . . . . . 8d6. . . . 8d6 . . . . . . . 8d6
.2d8 . . . . . 8d8. . . . 8d8 . . . . . . . 8d8
*If the base creature has an attack that deals no damage (such as a roper's strands), the attack does damage according to the "0" old damage row plus half the mystaran gargantua's damage Str bonus.
If the base creature has no attacks listed (such as a bat), it gains a single attack with the damage given in the "0" old damage row plus 1½ the mystaran gargantua's damage Str bonus. Use whichever type of natural attack seems most appropriate; it is usually a bite, slam or kick.
Mystaran Gargantua Modifiers Table
Size of. . . . Natural . . . . . . . . . . . . . Ability. Trample
Base Creature . Armour . Str . Dex . Con . Area . Damage . Damage
Fine . . . . . . Same .. +30 .. -2 . +12 .. ×6 .. +1d10 . . . 2d8
Diminutive . . . Same .. +28 .. -2 . +12 .. ×5 . . +2d4 . . . 2d8
Tiny . . . . . . +2NA .. +24 .. -2 . +10 .. ×5 . . +1d8 . . . 2d8
Small. . . . . . +5NA .. +20 .. -2 . +10 .. ×4 . . +1d6 . . . 2d8
Medium . . . . . +9NA .. +24 .. -2 . +12 .. ×4 . . +1d8 . . . 3d8
Large . . . . . +12NA .. +24 .. -- . +12 .. ×3 .. +1d10 . . . 4d8
Huge. . . . . . +16NA .. +24 .. -- . +12 .. ×3 .. +1d12 . . . 6d8
Gargantuan. . . +20NA .. +24 .. -- . +12 .. ×2 . . +2d6 . . . 8d8
Colossal. . . . +25NA .. +24 .. -- . +12 .. ×2 . . +2d6 . .. 12d8
Challenge Rating
Update the base creature's challenge rating according to the following table:
Mystaran Gargantua Challenge Rating Table
Old CR . . . New CR
up to 1/4 . . CR 5
1/3 or 1/2 .. CR 6
. . 1 . . . . CR 8
. . 2 . . . . CR 10
. . 3 . . . . CR 13
. . 4 . . . . CR 16
. . 5 . . . . CR 18
. . 6 . . . . CR 21
. . 7 . . . . CR 24
each +1 . . . CR +3
Absolutely! Ditto for the troll and gargoyle (and whatever other gargantua remain unconverted).
Do you mind if I have a shot at the Gargoyle and Troll?