Can I use outdoor version for indoor application?

 Yes, all outdoor versions could be used in indoor applications.

You can not use indoor version for outdoor application.

How can I tell if my transformer has real class 2 listing?

Class 2 transformers have limited output voltage, wattage and current protection.

Maximum output voltage is 30 VAC and 60 VDC (continuous). The maximum output wattage is 96W for 24V and 60W for 12V. The maximum circuit breaker for non-inherently limited transformers is 4 Amps for 24V and 5 Amps for 12V. Check if your transformer matches these three requirements.

There are two UL standards for class 2 transformers: UL1310 and UL1585-3. Please be aware, UL1585-3 does not cover DC transformers.  In order to avoid possible inspection issue, make sure to choose the correct transformer with correct certification.

What is max.ambient temperature?

The max. ambient temperature is the temperature around a transformer measured on distance1/2 inch from it. At that temperature the transformer could be loaded 100%

What is the load regulation?

It's relative difference of output voltage at no load and at full load.
α = [V(NL) - V(FL) / V(FL)] X 100%

What is transformer efficiency?

Transformer efficiency defined as the ratio of the output power Pout to the input power Pin:
Pout / Pin X 100%

What is a wire drop voltage

The wire drop voltage is a difference between voltage on a start and end or the wire. The longer distance, higher current and smaller wire diameter the higher drop voltage. These three parameters interconnected, so to know two of the we can calculate the third one.Here is the wire drop voltage chart where you find max. load wattage for given distance and AWG,  max. distance at given wattage and AWG or AWG at given distance and load wattage: 

What is Boost Tap and how to use it?

The Boost tap compensates a wire drop voltage at a long distance between transformer and lights by increasing output voltage by 10%.Use the Boost Tap only if the voltage on your lights less than 10.5V for 12V system and 21V for 24V system.First connect your power to the black transformer wire then check voltage on your lights. If your voltmeter reads less than voltage mentioned above, disconnect power from black wire, remove orange wire nut from the orange wire, cap with this nut black transformer wire, connect the power to the orange wire.Remember to turn off main switch when before  wiring.
Here is a wire diagram with and without using the Boost Tap:

What dimmer do I need to use with your magnetic drivers?

 You can use Magnetic Low voltage (MLV), Compact Fluorescent / LED ( C.L.)  dimmers . The list of compatible dimmers that was tested by EMCOD or our customers you can find here: Compatible dimmers 12-8-16.pdf