For me, minimizing triceps involvement is more a matter of elbow direction rather than hand position.
The elbows need to flare out more to the side for maximum chest activation.
Pointing towards your feet will call into play more triceps.
As for keeping delt involvement at bay, some guys prefer to stop the bar maybe 2-inches or so short of touching their chest.
Likewise, you can further reduce triceps involvement later in the movement by stopping the bar at about 4/5 of the way up, or whenever you can "feel" the triceps take over.
You may consider performing the movement inside of a rack with the pins & bars set accordingly.
If you're training for functional strength, then do the conventional all-the-way-down & all-the-way-up.
But, if you're training just to build a nice chest (it sounds that way), then IMO, it's better to keep tension on the pecs rather than transferring it at any point to either ancillary muscles or joints via lockout.