I say combo, have gps with the pattern emp, esg, rpg behind a wall, and than have that same pattern of vecs to reinforce that wall
if you are eden do emp thor gp, behind walls, and for vecs build them with this pattern 2 thors to 1 emp
try to put the walls in a v pattern in a narrow area, forcing the enemy to go into a increasingly defended area, and than after that have it go into a single tile pathway with gp and units on each side, have that for about 10 tiles, than it would open into a area surounded by gp, causing a huge bottle neck, and by than that force would be destroyd
if you are eden, and your oponent is ply with missles, space metior defence about a screen apart, so that he cant knock out your defence if he sends in a missle, and even if it does get through, always have a backup of lynx to send in the instant your tigors get empd
and always keep your wall and gp in good repair, its useless if you have big gaping holes in your defence