Now this is totally honest from me, (i'm not that good a programmer and maybe that's why) but:

a) you can create classes in pascal? I never went past record in datatypes.
b) OOP?? I just use functions and procedures inside units.
c) structure, depends on what I'm doing. But usually, Its simply based on the units I'd made previously.

But as far as I know OOP is better than procedural so why would you want to revert?

cheers,
code_glitch

PS. How do you make a class in pascal??