Melissa5,
I read your post last night. It sounds like you have a similar decision to make, though your requirements are definitely different than mine.
I have never shot a 4" model and don't have the opportunity to do so where I am located. I have shot a 6" model, however, it was a half-length shroud, not a full-length shroud. The former is generally thought to have superior balance when compared to the latter. This is undoubtedly true, but I don't have a problem with the full-length shroud version. It feels like an extension of my arm and is very easy to aim and hold steady. Granted, I'm 6'5" and have fairly strong forearms.
The main challenge for me is to nail down the issue of application. If I'm going to use it for hunting then I feel that I should go with the 6". However, if I decide to limit its use to woods carry and use my Blackhawk for hunting, then I feel that the 4"becomes a reasonable option. However, even then a part of me still wants the 6" for the longer sight plane and extra power. We all know what the real problem is. I want both! And therein lies the dilemma.
VTShooter