I don’t think 1500 as MTU for EoIP is a good idea here.
EoIP is 42 bytes overhead already. http://forum.mikrotik.com/t/eoip-tunnel-not-getting-1500-mtu/111523/1
The IPSEC overhead looks more complex than a simple number of bytes. It seems to be encryption protocol dependent also: https://packetpushers.net/ipsec-bandwidth-overhead-using-aes/
The only way I managed to get 1500byte packets over a VPN tunnel was with BCP (SSTP, PPTP or L2TP) which allows for a multistream connection and allows a larger L2MTU for the VPN connection. The fragmentation is still there, but on another place.
It is quite common to reduce the MTU to 1400 bytes for the data stream everywhere, with VPN involved. Works very well unless the application insists on having unbroken 1500 byte packets.
A bridge will adjust to the smallest MTU of the ports. But if the packet needs fragmentation somewhere allong the path , it is usually bad for the performance.