Geo...I don't quite understand the 45 degree angle attack. Elaborate further, or draw me a picture in crayon I can understand. I'll try anything.
Based on experience ( I know I'm no logger but I do split a dozen cords a year by hand with a variety of mauls, sledges, and wedges. Call me Stu Pidasso is you wish, but it keeps me young), I've found cutting a slot in the top of a log (standing upright, ready but unwilling to be split) is a mixed blessing. A long notch may seem to be the best, since you're essentially splitting the log via the saw, but I've notched logs almost in half and found my wedges just bouce back out due to the increased springiness of the wood caused by my notch.
Man, cutting them "lengthways" last weekend was a blast. As long as it's fun, why do anything else? My son thinks I'm going to wear out the saw doing that. Silly kid.....
Attached is some more black walnut to split (have three cords in the shed - good year).