I have seen many pictures of shotguns with side saddles and it looks like they would interfere with a left-handed grip. It looks like the closest shell will get in the way of your trigger finger.
Do any of you lefties have problems with gripping the gun because of side saddles? Would a pistol grip stock provide with the necessary grip placement?

Never ever ever ever had a problem.

The sidesaddle on my 590 sits way to high to get in the way. There's no way it would get in the way of your trigger finger. I don't see how this could be a problem with any shotgun. The saddle is just too high up to cause problems.

Spork,

I've had some complications with both my Mossberg 590 and my Remington 1100 Competition Master with different sidesaddles.

My 590 has injured me when I had some steel that wouldn't fall down in a 3-gun match.  I popped in a couple old rounds of 3" Remington Peters #4 Nitro mags to get the steel to go over.  After I got the steel down and the crowd picked their jaws from the ground (Big boom and flames in broad daylight caused my RO to jump back thinking the shottie had KBed) I checked out what was moist on my trigger finger,  Blood. The side-saddle, I think it is a Tac Star(or something like that, I'm at work) slightly intrudes down from the receiver and since it is aluminum and squared off near the trigger a proper hold must be ensured before detonating nasty rounds. (ie. hold on the bottom of the trigger, never near the top)

On the Remington 1100 CM, the sidesaddle is fabric and is therefore pliable.(Rem obtains these holders from 3-gungear.com I believe)  The last shell, closest to the trigger, can be a nuisance but all seems to work well and so far....No bleeding.

I like the 3-gun gear fabric holder more for comfort, but getting the shells in the holder is sort of a bear compared to hard plastic holders.

That's been my experience.

Sly