[IronDragon]

I would suggest downloading the items upgrade mod and get yourself the Ring of Preservation +2 made up. It provides a +2 to AC, +2 to all saves, and Regenerate at 1 hp/6 seconds.
This should more than compensate for AC shield bonus.

Never dual wield without at least two proficiency points in dual wielding and three is preferable.

The addition of the off hand weapon will only add one attack per round but in most cases that extra attack is worth it. Whereas the loss of an AC point can be compensate for in toher ways. I cannot recall who did the mathematical analysis of dual wielding but I do recall that the addition of the second weapon does an additional 30% more damage per round, (that 30% is approximate). Given your Str and Dex ratings I would think your THAC0 is rather good. Try an experiment and give your Ranger the second sword and look at your THAC0, it could decrease slightly for your main hand but not to a disastrous level. The gauntlets of weapons skill/expertise will help this and I recommend finding them ASAP.

Deul wielding is a definite plus epically when the weapons you are using deal out a variety of bonuses. My Ranger Cleric is dual wielding FoA and Crom Faeyr ( a traditional dual wielding combination) and at the start of ToB has negative THAC0 scores for both main and off hand. I also enjoy having Valygar dual wield Celestial Fury and DayStar.