Great stuff,
At least you've found that motherboards and PC cards are too fine, and no comparison to typical pinball cards.
If you want larger components+pads to play with, i STRONGLY suggest you pickup some $5 radios, cassette decks or old TV's from your local opp-shop.
Or, grab radios/TV's from your next council nature strip cleanup.
(although that might be a while away, assuming they do that in your area, not all councils do it).
Anyway, back to thrift shops or tip/recycling centres, keep an eye out for old tape decks & radios, they all have same size components as pinball cards.....
You'll then get a real good feel for how quickly (or slowly) your iron melts the solder, and how much solder to use when soldering components back in etc.....
hope it helps,
MM