I've used a lot of LC29 (it keeps well, unlike Ilfosol... but not in the Rodinal logevity stakes)
My FP4+ (EI 100) time is 6:00mins at 1:29 dilution @ 20C
Haven't souped many Delta 100's in it but at 1:19 dilution I've been hovering around 6mins too.
Since you mentioned Rodinal 1:100 to reduce contrast, I'd advise taking 30secs off those times to achieve that. My negs were printing G1 to G2 on a condensor enlarger and (now) with no filtration on a colour diffuser.