it depends greatly on what type of steel coaster. if it is inverted, i wouldnt go over 5 verts. if it is a sitdown type, i wouldnt go above 6.3. and please understand that you can not sustain those g forces over a period of time. for wood, i wouldnt go above 4.5. for negative g forces on all coasters, i wouldnt go above -1.3
for lateral g forces, i wouldnt reach pass 1.3 but for wild mouse rides there are exceptions. i woudlnt passs 2 lats for mouses.