Hi Jac,
You are right the connector for SPI is directly above (2mm) the ESP-antenna but they fit nicely.
It seems that I have to do a little bit resoldering of a few "jumpers" ( I have version 1.1 of the Dragino Board so no nice jumpers -bought it 6 weeks ago-).. but then it should fit the Wemos D1 like a glove.
I am taking small steps and at this moment I am trying to test the Dragino with an Arduino Uno first (afterwards I will resolder the jumpers on the Dragino)..