Your picture won't display for me.  Generally speaking, small gaps will get filled when you do fillets but 1/4" is a bit on the big side.  I'd suggest loosening the wires holding the forms against the bottom, pulling the bottoms panels together then retightening the form wires.  I assume that this is your first S&G build?  If so, you will find that things seldom pull together in perfect alignment and repeated loosening and retightening sequences are normal.  In addition to adding additional sticth holes, I find that the green Frog Tape pulled tightly across a gap on the outside helps close gaps.  The tape also keeps the fillet mixture from dripping through if it is a little too runny.     

Thanks Mark, Great tips.  I'll try adding a couple extra stich holes and perhaps the painters tape.  I did try some of the loosening and retightening of stiches and the rest of the panels have come together quite nicely.  Yes - this is my first S&G build.