1. is it possible to run clips slack on fixed gear or am i risking my feet coming out at 150 rpm?
Yes it is possible, but not too slack. My feet have never slipped off the pedal at any speed.
2. do you have to run clips tight?
No.
3. is running clipless worth the extra hassle of carrying spare footwear?
No.
4. do the benefits outweigh the inconvenience?
No.
Dear Sir/Madam,
The above is great sacrilege.
In this matter of opinion, the only opinion worth hearing is mine.
I have long believed this and I find all my own opinions utterly convincing and credible.
Clipless is the way to go on fixed-gear.
There is no other.
Taste the delight of clipless and the dull vanilla of rat cages will never appeal again.
I say "Pah!" to anyone who disagrees.