It would be helpful if you described which system it is. You could run the DB on a tech cam, but I guess it's a Mamiya body?
Anyway, in architecture images generally look better if you can exclude the ultrawide, perspective often becomes stretched out along the sides so it looks unnatural. However, the hard truth is that there's often limits on how far away you can put the tripod, especially in indoor photography. So you are left with no choice but to shoot with the ultrawide.
The 35mm will often enough be limiting on your DM33, especially if you can't shift it, so you should definitively go for the wider.