Need advice on stepper

I have to choose between two differents steppers. Theses steppers will
be use on a taig mill (3 axis). The drive will be Xylotex with
24VDC@8.5AMP PSU

Theses motor are convertible, can be wires in
unipolar/bipolar-serie/bipolar-parallel mode.

Which one is the best choice for my setup
bipolar-serie or bipolar-parallel
better PSU?
should I use 0.9deg stepper?
SST58D5831 have much more power at higher speed but what about the PSU
(24VDC@8.5Amp) with 3 motor like this one?

http://www.shinano.com/pdf/SST58D.pdf

SST58D5821
200 steps

unipolar
4.8 V
2 A
2.4 Ohms/phase
5.1 mh/phase
196 oz/in holding
138 oz/in@1000hz
67 oz/in@1500hz

bipolar-serie
6.72 V
1.4 A
4.8 Ohms/phase
20.4 mh/phase
274.4 oz/in holding

bipolar-parallel
3.36 V
2.8 A
1.2 Ohms/phase
5.1 mh/phase
274.4 oz/in holding

SST58D5831
200 steps

unipolar
3 V
3 A
1 Ohms/phase
2.62 mh/phase
196 oz/in holding
138 oz/in@1000hz
97 oz/in@1500hz

bipolar-serie
4.2 V
2.1 A
2 Ohms/phase
10.48 mh/phase
274.4 oz/in holding

bipolar-parallel
2.1 V
4.2 A
0.5 Ohms/phase
2.62 mh/phase
274.4 oz/in holding

Thanks,

Dominic Pageau