ASIO4ALL was considerably slower than the plain DirectSound driver mode (this was when using the Creative drivers). i couldn't use ASIO at all without horrible dropped sample glitching.
i changed over to the non-Creative kX driver to see if it was more efficient and it turns out to be much better. in ASIO mode, it provides me more "tracker power" with less CPU use. i recommend them if you need more efficient drivers.
http://kxproject.com/Sound Forge and ASIO... i think their ASIO support is limited to 44.1KHz and up (nothing lower). it complains that the driver is unable to support the sample rate/bit depth. when i switch to DirectSound (instead of ASIO) it plays, but has that odd noise after playing is finished i mentioned earlier. i assume ASIO & Sound Forge are simply not designed with the intention to deal with such sample rates since they're not considered modern or "valuable" formats. but MilkyTracker, Awave Studio and Renoise have no glitching on playing these low-rate samples (even with Renoise and Milky Tracker using ASIO - i assume they're mixing at 44.1KHz, where Sound Forge tries to play a sample at its native rate and then runs into driver issues). so, all is really ok in the end.
as for tuning... i have a neurological impairment that makes calculation/math and other number stuff hard for me. ironically, i'm a tracker user... hah... (i'm better at using references for effects than remembering the effect codes, and i'm not very good at utilizing them like really good composers, but i get by). so... i'll keep plugging away at it and maybe figure it out with the info you've provided and experimentation.