I have tried to develop DELTA 100 in a couple of combos, but I found to get the nicest tones in Rodinal 1+50 with the film rated at ISO 100 or 125. The times are between 14 and 17 min.
Another way I use this film is rating it at ISO 64 and develop it for 10-12 min. in Rodinal 1+50. This gives me rather high contrast for experimental portraits, especially modern fashion work with harsh studio flash.