How far in should the Slip Yoke be....904

Supershafts......Thanks. This is why I got on the forum for my question. The local shop just told me to bottom in the trans and then pull out the 3/4 to 1", but the dilemna was the dust boot on the seal as noted in the original message. The yoke is pretty long and I am sure there would be gobs of engagement even if the radius edge of the yoke was 1/2" to 3/4" from the back edge of the seal boot. Just trying to not do anything wrong.