Perfect enchantment shield?

What would be the req and stats of a perfect enchantment oriented shield that req tactics?

Well for perfect inherent mods you would have:

+45 health (enchanted)
-2 damage (enchanted)

The req is subjective - some say only req8 versions would be perfect, while others believe that the inherent mods make it perfect, not the requisite.

+30 Health always with -2 damage enchanted is also considered perfect.

+30 Health always
-2 damage enchanted

...is also a combo on the same shield?

It is a potential combo on any shield, yes. You won't find both +30 always and +45 enchanted on the same shield, it will always be one or the other.

what are the always stat combos like?