[tsubaki]

Congratulations on the V!!
It has been my assumption, the way you use the trailer dictates the the setup of it.
I'm partial to bunk type trailers with rollers contacting the keel, sharing the weight evenly with the bunks.
Other people simply use the rollers as a protective bumper when at a hoist or a good ramp that will allow floating the boat off.
Be sure to have at least 8 foot of bunk contacting the bottom (I see you do) or lower them so as to also contact the rollers with the keel. On lesser made boats, I've seen short bunks deform the bottom of the boat from too much weight on them. Also I've seen hooks in the keel from a trailer setup with only 3 keel rollers and the bunks barely contacting the bottom.