Which tap??

[Jonathan]

Typically I just buy what I need size wise as and when I need them

...and end up spending more in the long run than if you had bought a set. I bought one with had the standard 3 of each tap, and dies from M3 to M12 a couple of years ago and it's been invaluable. I've since replaced a few, generally with odd ones I find at the car boot sale.

I think some people use a little lube when tapping, personally I don’t bother.

Then you're missing out. Use something with a low viscosity (WD40, coolant, tea...) works well for aluminium and a tapping paste for hard materials. It will make the taps last longer and increase productivity since if the tap is lubricated you can often get away without periodically reversing.

Also can you hand tap with a spiral point?

Yes, so long as it is not a blind hole a spiral point tap is generally the best choice for aluminium.

I believe the standard preferred metric screw thread is the coarse thread.

Correct

P.S. Anyone want to come and tap about 1000 M8 holes for me ;) ?