How tight should tri cycling shoes be?

Spins

I just got a pair of tri specific cycling shoes, Shimano TR02's. Got them online (I know, prob shouldn't have, but I did) for a good price. Tried them on and they felt fairly comfy, less room in them than my training (road) shoes. There's plenty of room to wiggle my toes even tho they're right up by the top. A mate just told me that ideally they should be extremely snug all round with no/minimal movement. Should I return them and go a half size down? Thing is I was hoping to use them the next couple of nights ahead of the Valentia Tri next weekend.
In terms of boardsies normal size shoes/runners, how do they compare +/- sizewise to their cycling shoes?
Any thoughts on how tight the shoes should be would be appreciated.

tunney

then need to be very snug - not uncomfortably tight but snug.

My tri shoes and road shoes are the same size - then again they the same brand.

If you're foot moves in the shoe at any stage during the pedal stroke then they are too loose.

hunnymonster

if your feet can move they are too lose, if you get hot spots they are too tight.

I have bike shoes in two sizes, the same as my run shoes for longer spins (and for hot weather) and a half size down from this for shorter bikes (where I go without socks)

Spins

Check out what this guy says.http://www.bikesportmichigan.com/features/shoes.shtml
What do you think? His feet look way too crammed in for my liking...