Hi All and Happy New Year
Not sure if this is the best place to write, but I figured some of the people here would know a lot about cooling electronic stuff!

I just got a new amplifier (which I love) and I need to get some additional cooling for it (it gets hot sometimes). The amp sits on a shelf; open at the sides front and back (see image). There is a gap between top of amp and the shelf above of 35mm; and a gap below of just 20mm. I was thinking about putting either 2 x 180mm fans or 1 x 250mm fan on top of it to draw more air through.
The questions I have are (please note that cost is an issue!) :
1. Would I be better with 2 x 180mm or 1 x 250mm? And is this likely to be enough?
2. What is the best way to power the fans, i.e. easiest, quietest? There is a PC nearby.
3. Do I need to box the fan(s) in at all (close in sides/back) and perhaps use extra smaller fans to vent the hot air backwards from the shelf?
4. Can the fans be controlled in any way, e.g. manually or with a temp sensor on the case?
5. Is using a laptop cooler a good way to go? Thought they might be too noisy, push the air the wrong way, i.e. down and not up, or just plain not suitable...
I know that's a lot of questions, but I'm not sure what the best thing to do is. Hopefully I will get some replies to point me in the right direction.
Thanks