First I've heard the 'tape head saturation when recording the tracks' stories. But I've heard early live recordings that rival the studio albums so it's possible to get that sound without all the mojo.

I came to these conclusions, mid to heavy distortion without loosing control of the sound through squeal and to limit the high end by cutting above 3KHz. Limit the low end to remove that booming and mushy sound by cutting below 300Hz. And most importantly using an EQ and boosting 500 - 800Hz to get that mid range that sets the sound apart. The amp used has a factor in this but I tried to use neutral tone settings and let the pedals do the talking. So far I've been pleased with the results.
Looking forward to hear your comments.
Brad