Side effects and percentages not disclosed RE radiation

Hi all. I’m in the fortunate position of being able to choose on the type of surgery I have, but regardless of whether I have a lumpectomy or unilateral mastectomy with DIEP flap reconstruction, I have to have radiotherapy :(  My dilemma is that I’ve received conflicting advice about when to have radiotherapy if I choose a mastectomy. One Dr recommended I have it before reconstruction, the other recommended I have it after reconstruction. I’d love to hear your thoughts.