Clark, there are two sets of rules that work together, one that defines the game play which the others before me have talked about, and the other that defines the equipment.

Here's what I observe (Danville veterans could feel free to clarify or correct me):

A set of really specific regulations existed and apparently was used back in the day of super-serious tournament-style battles, and detailed scale speeds based on actual historical data, among other things. I've not seen that being used in the series of battles I attended there from 2013 till now. No one seems to be too hung up on speed anymore, unless it was really zipping around like a offroad buggy.

What I do observe is that, depending on the club hosting it, they would specify apple configurations - stock Tamiya, with the 3-6-9-12 o'clock vulnerable configurations, TFA with the pyramid rotated 45 degrees, or IFA where the apple's frontal quarter is blocked with tape to simulate impenetrable front armour, depending on tank type, they may get varying widths of tape.

IR apples should not be blocked, intentionally or otherwise. It isn't entirely clear to me if the apple is blocked by a stock feature of the tank (e.g. commander's hatch in the case of the Tiger I) whether it has to be removed.

IR apples also don't get deliberately lowered, the hit indicator LEDs must be visible. Similarly the gun muzzle flash and/or recoil mechanism must be functioning. This gives visual indication of firing and taking hits.

In all cases, damage simulation is necessary, the tank must slow down sufficiently after taking damage.

For some battles, the IR emitters are checked for correct depth and diameter, and for turreted tanks they always stay aligned with the IR apple. Casemated tank destroyers get some off-bore slew but they don't have the luxury of turret rotation. I have not seen a tank with more than one IR emitter, so I assume that is not allowed.

Tanks must have their volume turned up loud enough to be audible - no stealth tanks!