Im needing a few suggestions for good mic placement.

Running a marshall 4 x 12 cab and the speakers are Celestion Classic Lead 80's and t75's in an X pattern.

Mic's are Oktava mk319 large condenser and EV Cobalt Co4 running into a M-Audio Pre-usb

Also how should i dial in the gain... Do you make them both equal or like a 60/40.. And do you normally set them up were they clip then back off a hair or keep it were the green light just barely flashs..

Thanks for the help.

Also music sytle is Metal at low volume bedroom recording.
Microphone placement is entirely subjective. On axis, in the middle of the speaker, yields a brighter treble-ish tone. The further you move towards the edge of the speaker, the bassier it gets and the smoother the highs get. Turning the microphone off axis will result in coloration of the highs and mids for different tonalities. Try multiple positions and see which sounds best to you.

Your preamps and their respective channels in the DAW should be peaking in the -6 to -12dBfs range. Never set your gain where nominal levels are directly below clipping, as any transient peaks will be lost and distorted by the digital dB range. Dial them both in to this gain range, and set the appropriate levels and balance in the DAW.