Verizon wireless gateway and cellular MTU value

RouterOS General
1

I recently changed ISP to Verizon wireless gateway.

Today, I decided to do a test for maximum mtu.

ping -c 1 -M do -s 1400 1.1.1.1
PING 1.1.1.1 (1.1.1.1) 1400(1428) bytes of data.
1408 bytes from 1.1.1.1: icmp_seq=1 ttl=50 time=32.5 ms

--- 1.1.1.1 ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 32.471/32.471/32.471/0.000 ms

On my mitroik router do I set all my interfaces to use 1428?

Do I need to change the L2 MTU? 1428 + 14 = 1442 ?

Is there a simple command to change them all at once?

TIA

2

If you do:

/system/default-configuration/print file=config

You will get the default script to a file called config.txt, why not use that file to learn some Cli Mikrotik Commands and script technics.
And how many interfaces do you have ?