Advice please - Epoxy resin shower corners

[NeatOne]

I have been searching for information on internal corners joints for shower. I have epoxy resin which I have used to join mitred tiles on a difficult angle external corner. Is I OK to use epoxy resin in joint on internal corners? I plan to use epoxy grout for remainder of shower. The shower has waterproof backer board and wedi shower base which will be tiled. Can I use epoxy grout between wall & floor tiles or do I need to leave expansion gaps? ( I know industry standard recomend silicone with expansion gap but was unsure about epoxy resins) Thanks

 

[Phone-a-tiler]

Silicone should be used where movement will occur. Internal corners and wall/floor joints and around pipe protrusions