nitinarora:
My questions apart from critiques on the general thought process, is on the viability of using an N channel MOSFET such as one of these (depending on availability):IR540N
IRL2203N
RFP3060NLE
FQP30N06Lfor my setup. Would I be better off using a transistor such as the TIP122 or should I go the MOSFET way.
Don't use TIP122 or any other darlington, they have high voltage drop which depends to some extent on the current you are passing through them. As a result, you may have difficulty getting enough voltage to drive the LEDs, and the brightness may reduce as you turn on more LEDs in that layer.
The IR540 is not suitable, it is designed for 10v gate drive, not 5v. IRL2203 is suitable. RFP3060 I can't find, maybe you mistyped the part number. FQP30N06L is also suitable.