My first bench, need some input

[James Williams 007]

I have started to build my first bench and I need some help with the basic design. I was originally going to construct it all out of SYP but I started to think about the wood I would use for the outside edges and the vises and because I had some walnut that has been in my shop for over a year I thought that would be a good choice. I would like to glue the front and back edges of walnut and then bolt the ends on. I would slot the end bolts to allow for movement but my biggest question is should I worry about gluing the walnut to the SYP. Both woods have been in my shop for over a year and are well adjusted. Walnut has a radial movement of 5.5% and a tangential movment of 7.8% and SYP has a radial movement of 4.8% and a tangential movement of 7.4%. Both of these woods are similar in there movement characteristics and I tried to alternate the grains and when I milled the SYP I tried to get as many in the quarter-sawn orientation as possible so I am hoping that the top of my bench is pretty stable!? In my picture you can see the peices of one of my leg assemblies layed out what do you guys think about using a nice mortise and tenon to join the front and back legs together? I plan on using a wedged dovetail type joint for the side to side stretchers like on the 21st century bench. I would be grateful for any suggestions or info any one might throw my way.