The valve job I did earlier changed the valve clearance a tiny bit as it will position the valve further into the seat.  The MZR uses bucket between the valve and the cam that acts like a shim. They are numbered with 3 digits which is actually  the three decimals of 3.xxx mm.

The gap should be

IN: 0.22-0.28 mm {0.0087-0.0110 in}
EX: 0.27-0.33 mm {0.0106-0.0130 in}

The process is pretty straight forward as described in the FSM



I was already on the low side after installing a 2.0 intake cam and was off on 3 buckets and very close on several others.

I had to put everything in a google sheet as I ended up juggling 32 buckets including 16 left over after my 1.8 engine.
The new values colored green,blue and red was found using the formula described in the FSM:

New shim= Removed shim thickness + Measured valve clearance - Standard valve clearance (IN: 0.25 mm {0.0098 in}, EX: 0.30 mm {0.0118 in})


STD Intake clr0.25
STD Exh clr0.3
Intake
Cyl #12345678
clearance0.250.230.210.230.230.210.230.23
Shim3.2823.3223.3023.3023.3023.3023.2623.262
3.2823.3023.2623.2823.2823.2623.2423.242
Exhaust
clearance0.350.30.30.30.30.30.30.3
shim3.2823.3823.3423.3823.3823.3623.3623.422
3.3323.3823.3423.3823.3823.3623.3623.422

I only need 3 new shims after swapping buckets all over the place.

The part numbers for the buckets are listed as one partnumber (1F2012300B ) on www.onlinemazdaparts.com but there is actually one partnumber per size as described here  under  12966 "DISC,ADJUSTING"

Just out of curiosity I checked the part numbers for the valve springs and intake cam on the L5, NC1 and NC2 engines since NC2 supposedly has springs that can take more RPM:

EngineValve springIntake cam
L5VE (2.5L)LF5012125AL3G212420A
NC1 (2.0)LF5012125AL3E312420
NC2 (2.0)LF9G12125AL3E312420

So, if you want to rev the L5 or NC1 past 7K the springs from a NC2 will be a cheap upgrade.