b. Amount of center cut really doesn't change fletching requirements, but does affect spine requirements. An improperly spined arrow will hit the riser. Brace height and nock point height also affect arrow clearance. A brace height that's too low can cause the arrow to slap off the side/sideplate of the bow, and a nock point that's too low can cause it to slap off the shelf.
First some definitions. A bow that is centershot is cut past center, usually 1/8 to 3/16 of an inch. A strike pad will bring the sideplate out a little bit so when the arrow is on the bow, the string will usually bisect the arrow, i.e., centershot. In my opinion, these are the hardest bows to tune an arrow to. Because the arrow is lined up perfectly centered, it doesn't know which way to flex as its leaving the bow. Not a problem with compounds and trigger releases, but it is with finger releases. Need to do one of three things. Shoot a larger diameter arrow, build out the side plate and/or increase the spine considerably above the bow draw weight at your draw length.
Bows cut to center are easier to tune, IMO. With strike plate material, the side plate is actually a little left of center for a right handed shooter and the arrow will be pointed left of the string (for a right handed shooter) when on the bow. The arrow will need to flex around the riser as it's shot to go where its aimed. Luckily, it's pretty easy to find the correct spine to yield just the right amount of flex.
Many bows, particularly D-style longbows, are cut 1/8-inch from center. Adding strike plate material on these moves the effective side plate even more left of center (for a right handed shooter. There must be something about the degree of offset this imparts to the arrow being particularly compatible with a finger release, because I've always found these types of bows with moderate r/d and straight designs to shoot a wide range of spines well.
A very thick riser, side to side, can sometimes cause clearance problems if the bow is cut to or past center, even if the arrow is well tuned to the bow. Turning the cock feather in will improve clearance, but may not solve the entire problem. If that's the case, raising the nock point as high as you can get it and still get good arrow flight will usually yield the clearance necessary.
Quite a long diatribe. Hope I've answered your question.