I thnk the dillon is similar to the lee in that the dies are mounted to a plate you change, so once adjusted they stay that way. Changeover on that and shell plate is 3 minutes maybe.
I shoot 9/38 so use the same primers, nothing to change. YOu'll have to change primer feeders/primers. Time depends on the press you choose.
Case feeder - on the lee the 9 and 38 take different ones, changeover is 3 or 4 minutes. No adjustments needed.
Powder of course needs changed, if not type at least load. This takes me another 4 minutes maybe.

To on a loadmaster changeover is 10-15 minutes. I try to load enough of one caliber than I can go a month or more before needing to change again.

What most around here do is spend the winter loading for the summer. I'll do that this winter also. I know for PPC I need 1200 rounds of 9 to compete plus whatever I want to practice with. If I can make IDPA shoots I could potentially do 12 of them at 150 rds per. Then after PPC there is the Invitational (200 more plus practice) and then we shoot steel plates till the end of october. For 38 practice plus 600ish for competition if all I do is the snubbie class at PPC.

At even a low count of 350/hour from my loadmaster those what, 3500 rounds, will take 10 hours spread over a few snowy saturdays. Changeover won't be a concern really.