Mike
The wheels sound good! Your offset is a little outside the VW spec (30 - 39mm) but just by a couple of mm so should be fine. It might just make the steering a little heavier. No spacers needed.
The centre bore is easily big enough to clear the (59.2mm) front greasecaps so no prob there.
I've no experience of drilling out holes (I'm assuming you want to widen each hole a little), so can't help you with that one.
I'd imagine tyre profile would be 50 or 60, depending on the width of tyre the actual fitted. There are lots of tables available to ensure you keep the same rolling radius. It's worth noting though that T3s need a tyre with a load rating of at least 92.
Lowering won't be a prob if the rolling radius is kept the same. Most people suggest a max comfortable drop of 45mm, but it's a free country!
Good luck!
Simon
Edited by SimonH