Mid cannelure should be fine. Don't get too bent out of shape over OAL. If it'll go through your magazine and chamber without problems, you probably aren't too long.
The minimum load for most any 55 grain bullet would be a pretty good place to start. Work up slowly, looking for high pressure signs. I'd go with a load for the bullet that is as close to the one you are loading as I could find. Different, shapes, ogives, etc. can have a minimal effect on pressures; but not usually much.
One caveat is that loads for the all copper projectiles will be different from lead core bullets. The all copper bullets will be longer. That means more bearing surface, and in turn it'll take more pressure to push it out the bore.
As far as crimping goes, with 55 grain fmj bullets, I get slightly better accuracy with crimped loads than non crimped loads. You'll not know until you try it both ways.