If any of you wishing that your thunders are higher, just take out the stock bottom bushings on those thunders in put aftermarket connical bushing from independent.
If you want to make it exactly indy standards high, add another small washer in the bottom washer in addition to the indy connical bushings.
Not trying to be a dick, but none of that washes. Thunder bottom bushings are taller than Indy's. So your first piece of advice, it's just going to make the Thunder sit lower. Adding a washer under an Indy bushing would make it... normal Thunder height. If you want taller Thunders, use a riser.
Unless you're talking Thunder lows. In which case you'd be throwing the geometry off hard enough to start stressing things like the kingpin. Not a good idea.
From a physics perspective, indys suck. They are bricks.
Less weight = easier everything.
Someone should make a test where they have X amount of setups, all with equal WB and tail/nose angle.
Its the only way to leave out stuff like different leverage and turning radious duo to the trucks different WB.
The difference between standard cast versions of Indy, Ace, Thunder, and Venture isn't that drastic, within 15-20g of one another. If you start adding forged plates and hollow steel, then you have some actual weight differences. Perceived weight due to wheelbase lengthening however is a thing to consider.
Went over that in one of the 9 truck threads going on, if you wanted to have that level of control over testing situations, where you can tailor different decks to feel the exact same with different truck brands, you're going to be ordering custom one-offs per set up, with different molds for each one.
Also, seriously, there's way too many truck threads happening simultaneously right now.