Im too am experimenting with shallots as well. I planted them this spring and they seem to be doing well.

http://www.flickr.com/photos/odalaigh/3621257294/
http://www.flickr.com/photos/odalaigh/3620438449/

From what I read the larger shallots should be planted because they do not store as well as the small ones.

The winters here in Norther Michigan are quite harsh so I plan to do some testing. I will replant 1/2 this fall then replant the rest in early spring (March).

Back in the olden days, before anybody sold onion plants and the general store did not even carry sets, country folks relied on potato onions ( shallot is fancy name). These are multiring aggregate onions. The prettiest largest onions were saved overwinter and planted as soon as the groun thawed and dried in the spring. These would form dozens of small sets in the course of a summer. The small set were planted in early spring and would grow into one ( sometimes two or three but the goal was one)large onion. Very labor intensive for the amount of onions harvested, so as soon as sets and plants were available most folks abandoned the potato onion. As an aside, they were use as green onions or cooking onions, quite pungent.

odalaigh, your shallots look great! Mine are in bare soil, but a small enough patch that I don't need the weed barrier 'cause it is easy to hand weed. farmerdilla (nice moniker), I guess the lesson is that your answer gives me the advice I wanted - big ones give large quantities of smaller shallots, small shallots give fewer but larger bulbs. I just flat like the taste of shallots vs. onions in certain dishes. Our onions (yellow Granex) are humongus this year with all the compost and rain.
I will plant some of both sizes both fall and spring and figure out what works best for me here in KS, zone 6A.
Thank you both for your comments!
hortster