Why would you want a 29 inch shaft if your draw is 26 inches. Most folks who shoot woodies leave about one inch behind the point protruding beyond the back of the bow. Unless you need the extra length for extra arrow weight, really isn't necessary to have the additional length.
I think something in the 55-60# range would work nicely. Generally, a rule of thumb is to subtract 5# of weight for every inch below 28 inches one draws. Likewise, one usually adds 5# of draw weight for every inch beyond 28 inches one draws. Your draw length is 26 inches regardless of arrow length so adding spine weight because of increased arrow length is not the way to go. Though the longer arrow does have the effect of decreasing dynamic spine when shot, it's not a big factor at a 26 inch draw.
On the other hand, one usually adds 5# of weight for a fast flite string, which I assume your bow has, and another 5# for a points over 125 grains, in the 160 grain range. So, following general rules,we've subtracted 10# of spine and added 10# of spine to the the 50# at 26 you're drawing. Nul sum game to this point.
If the bow is cut to center rather than 1/8-inch from center you might add another 5# of spine (another rule of thumb). Finally, on high performance bows (extreme reflex/deflex) it's also a general rule of thumb to add another 5# of spine. Not knowing whether your bow is cut to center or not, and assuming it's a good performance but not really high performance bow, I'd err of the safe side and add 5#-10# more. Even if it's not cut to center or high performance, most bows shoot woods spined a little heavy better than they do woodies spined right at or below bow weight. Good luck.