Confusion about 833 4 speeds

WHat are the pros and cons about using the 26 spine rather than the 30. I do not plan on racing the car but it will be driven with spirt.

It appears from what I have read, that the 65 and earlier trans had the flange type drive line and yoke and the 67 and up used the 30 slpine slip yoke. Only the 66 had the 26 spline slip yoke. Can I take anything from that as far as reliabilty?