Manny, I've only done a few sinewed bows and 2 of them are 60", which worked out well for me. I believe sinew is better suited for shorter bows with 63"-64" being on the long side. I think I'd go with the 58" and add the sinew only to the working part of the limb and leave the tips bare wood(under the finish). I usually leave the tips bare on sinew bows to protect the sinew from the string and vice versa. I then wrap where the sinew ends.
That shorty is stunning with that dark streak in it and the long tapered outline.
My next sinew bow is gonna be a 50" ERC bendy handle bow with sapwood and heartwood. Pat