Pano shoots have dark area on sides !

Hi. As you may imagine, I'm new.

My issue in this topic has to do with shooting the pano images correctly (spherical) for stitching and for later use in TW:

(1) After taking my spherical pictures and stitching, the areas along the stitches (meaning, were one image overlaps another) are darker than the rest, giving off were the two images have been stitched. I am thinking it has to do with poor lighting when shooting, but I wanted to know if that's what you experts know might be the issue, and if so, should I need a light fixture or something? (I am using a Nikon D80) 

(2)Resolution: any minimum requirements? My D80 has RAW, and JPP Fine etc. How much is too little, How mush is too mech? What is the correct format for working in Pano and TW?

(3)Celing: If ceiling has a Fan or light fixture, how to shoot to ease stitching later?

(4)Floor: After shooting my 4 angles and ceiling, how do I shoot the floor? I am guessing I will remove camera from tripod, and stand in a high place (a chair) and try to shoot above the spot were the tripod was, and then import it to photoshop and overlap it? If so, do I shoot it also with my sigma fisheye lens or regular one?

(5) I have an issue trying to use my 1st Spherical image on TW. If I use a "sample" image from the software, and preview.. good, If I use MY image, which work fine an PW preview, .. I just  get to see the skin. Do I need to save it a certain format or way for it to work fine in TW?

Hope this were not too many questions in just one topic, but they do cover the basics for statup.

I will appreciate any help on getting started with the right foot, and though most of you chiefs are experts, there are always new guys like me hatching into this world and need help. I'm guessing I will get many more issues along the way, and I hope I can count on this forum to learn how to walk. Thanks

(1) This is most likely to do with lens light fall off (Vignetting) and this is corrected when you process a RAW image file correctly. The other issue will most likely be if you are NOT shooting in (M) manual mode so too keep the exact aperture, shutter speed across the whole range of images in the panoramic set.

(2) You should always shoot in the highest largest setting and resize only the final process panoramic image. Tourweaver has limitations across versions that differ and also image compression (maximizing) play a HUGE part.

(3) ? Makes no difference. Turn the fan off if you don't want the blurred motion look.

(4) Crawl before you can do gymnastics! Huge leap from shooting and stitching from the panohead to handheld. But typically you would shot the down shot "Nadir(B)" handheld at the same height as the panohead (no chair involved).

(5) I can only guess here that the image is far to large in both pixel dimension and overall weight. Resize the panoramic image to say 2800x1400 and "Save for Web" in Photoshop at say "70" and see if it will then display. Also, if it is being added as a spherical image be 100% sure it has a exact aspect ratio of 2:1.

Regards, Smooth