1) D1.1 and B2.1 are different animals. Your customer's spec should spell out which code.
2) AWS D1.1:2006 Table 4.10 2G test qualifies for production plate fillets welds in the F and H positions, production pipe welding in the F and H positions(with note h), production box tubing welding positions F and H(with note h).
note h says to see 4.25 and 4.28 for dihedral angle restrictions for plate joints and tubular T,Y, K connections.
3) D1.1 covers 1/8" to unlimited depending on the thickness of the test coupon(1/8" to less than 1" test coupon qualifies for 2T, 1" and over test coupon qualifies from 1/8 to unlimited). AWS D1.3 is a sheet metal code to cover guage materials up to 3/16".
4) see my answer for number 3 and also see Table 4.11 in AWS D1.1:2006.
5) there are software companies out there to help with the record keeping and creating of WPSs, PQRs, and also WPQRs but you still need to know how to properly interpret and apply the codes.(the human interaction factor is still required)