Thane -

M&T at that location may remove too much material. I usually do the girt shoulder joint with lags. You need to figure out how much relish you need, and then you run in lags from the top.

As to jack rafters... do not M&T them. Housing of appropriate depth with panel screws or lags from the top. You can do an adzed or band saw reduction curve to bring the jacks down to size so they fit in the hips.

And - you may not need to push the hips all the way up to a fine point. A 1" or slightly larger flat on the top works just as well. If the jacks are properly sized, you can always up the size of the hips to make life a bit easier.


Here are the screws I like:
http://www.ozarkloghomes.com/loghogscrew.html