Rough guide for seat fore/aft position (and pedal cleat position): Spin a few times on a trainer, stay in the cleats and gradually roll to a stop with one foot in the "3 o'clock" (pointing forward) position. Have an assistant drop a plumb bob holding the top of the wire/string on the little bump just below your kneecap. The plumb bob should point to about 5-10mm aft of the pedal shaft. The old "standard" was to drop the plumb bob right from your kneecap, and it should point right to the pedal axle. Either measure should get you close.

Another possibility - wrist angle? Based on the angle of the brifters on the bars (presuming you ride on the hoods most of the time). While in the saddle with the bike on a trainer, let your arms hang down to your sides, or forward toward the bar, and pivot your wrists "up and down", as if shaking hands with just your wrists, and try to find the "neutral" position, where you're not really "pulling" it either up or down. NOTE: this may NOT be the same position as your hand visually "straight" relative to your arm. In my case, my wrists feel "neutral" when my hands are slightly "down" (toward the pinkies), maybe 10 degrees. Anyway, try to hold your hand in that position relative to your lower arm, and lean forward to put yourself in position, with your elbows at the angle you think is right, to put your hands on the hoods. As you put your hands on the hoods, if you have to rotate your wrists "up" or "down" at all to get your hands to rest square on the hoods, that means you're holding your wrists in that non-neutral position for much of your ride. If it's "down" a bit, it's might be an issue. If it's "up" a bit, you can get numb and/or tingle-y pretty quick. You can demonstrate this yourself just by moving your wrists in this plane up and down as far as it will go; you'll notice as you approach the "up" limit, you can feel it start to pinch.

To adjust, you can rotate the whole bar up or down to change the relative angle of the brifter hoods, or, if the bar was taped properly, you can move the brifters up or down a few degrees on the bar.