I wouldn't glue it anywhere. You're asking for trouble if you do. Use the clips you mentioned or make your own. I usually cut a 3/8" dado on the inside of the apron 3/8" from the top, forming a groove which runs all the way around the inside. Then I crosscut several 1" lengths of a
3/4" hardwood board, and I rabbet it to form a 3/8" tongue which mates with the groove on the inside of the apron. I crosscut the 1" strips, rather than rip them, so that the grain runs perpendicular to the tongue, making it stronger. Then, to attach the table top, just set it on the apron, place a couple of your homemade brackets on each side and screw them in to the bottom of the tabletop. The depth of your dado (and depth of the tongue) will depend on what kind of movement you expect out of the wood. You mentioned that your tabletop should grow by 1/4" at most, so I'd make them both about 1/4" or 5/16" deep and screw them into the tabletop about 1/8" away from the apron. If you think it might grow a little more than that, you can oversize the screw holes in the brackets so it has room to slide a little if necessary.
Funny story: The first time I ever made a table, I did it in the summer and gave it to my in-laws for their kitchen. It was fairly small, maybe 40" wide or something like that, made of maple. Like an idiot, I fixed it directly to the apron without allowing for movement.
5 months later, on Christmas day, my in-laws had a get-together at their house. This was in Maine, and that particular Christmas I remember it was ridiculously cold, 32 below zero when we got up. Well, my mother-in-law cranked up the wood fire and got the place roasting inside, so I'm sure the air was a dry as the Sahara. Sometime in the afternoon, we were all sitting in the living room when all of a sudden we heard "POW!!!!", like a gunshot from the kitchen. We all ran in to see what had happened, and it turned out that the tabletop had split right down the middle! There was probably a 3/8" gap in that sucker. Took me a couple of weeks to get everything fixed and reattached correctly.