Designing The Smallest Wye-Type Turnaround

[chasbl]

Can someone tell me how to design the smallest wye-type turnaround using the HO gray-roadbed E-Z track?  By smallest I mean the turnaround which will take up the least area on my layout.  My locos will navigate 15" radius turnouts and 15" radius curved track.  Should I use a wye and two turnouts or should I use three turnouts?  Which various wyes, turnouts and track pieces will I need to buy and how will I assemble them?
Many thanks!
Chasbl

[Steam is King]

Smallest Wye is a No 4, which will require you to use 18" radii curves. Your Wye will be concave on all three sides. Here is what it will look like: