anyone have any suggestions on preventing my top cake layer from squeezing out the cream filling?
Ahhhh, the battle of the bulge. Been there, done that.
Are you putting a dam on the outter rim of each layer. The frosting dam will help to keep the filling in the center. Also, wait a bit before frosting the entire cake once you've torted and filled. Waiting a bit will allow gravity to let things settle.
Hope this helps.
Welcome to CC! Some people also add cake crumbs to their BC when making the dam. Tastes great & gives the BC more body to hold in the filling. It's also used for "repair work" on the cake itself. Either way has worked for most of us so just find what works best for you.... straight BC or BC/cake crumb combo.
Add the dam .... only add filling to about halfway or 3/4's up the side of the dam. When you add the next layer, give it a good push-down. If any of the dam bulges out, use the spatula to smooth it When I have "concave" spaces on the side of the cake, I take a decorating bag with coupler but no tip and fill in the gap ... then smooth it with the spatula. Let sit for a bit.
Here's the best tip(s) on preventing bulging: http://www.cakeboss.com/PreventBulging.aspx