Hi,
I think what you have setup is correct only…
thanks… 
I’m not sure if you’re running a WISP, but this MUM presentation I did will probably be helpful.
Essentially you need to set MTU in 3 places:
L2MTU on the interface
MTU (which is Layer 3) on the interface or VLAN - This is 1500 by default which is fine for VPLS but if you want to test larger packets with the DF bit set using the ping command, then it needs to be raised.
MPLS MTU
The other two MTU settings you mentioned are likely:
VPLS MTU
Bridge MTU
Unless you need to pass an L2 frame larger than 1500 inside of the VPLS tunnel, then you don’t need to modify these
Here are the minimum values for MPLS with and without VLAN tags
The MUM preso is here:
https://mum.mikrotik.com/presentations/US16/presentation_3327_1462279781.pdf
Nice Presentation 
L2 MTU for the interfaces that carry MPLS labelled traffic has to be set to at least as high as the MPLS MTU for the network. The MikroTik default L2MTU is often around 1596 or so, we never bothered to lower this.
We use an MPLS MTU of 1550 network-wide - it gives more flexibility in case we or the customer needs Q-in-Q or slightly oversize packets for some other purpose.
Whenever we turn up a VPLS tunnel we always do a ping test from one side to the other with don’t fragment 1500 bytes and make sure it is successful (unless the customer needs more, then we test for more). MTU restrictions can result in some packets being dropped, or one side of the tunnel coming up but not the other.