Skip,
These arrows are brand new for the hunting crowd but have been used for target shooting for a few years. So there's no 100% here but I've always seen smaller diameter shafts penetrating better than larger shafts. I shot gold tips for a few years and they are a great shaft. The last few years I've been shooting Easton Axis which are smaller and I must say slightly heavier. But I consistenly seen more penetration out of my axis shafts than larger shafts.
Now I'm a little handicapped to begin with. Short 27.5" draw length so I need everything I can get. Anyway I would shoot with 29" guys 30" guys that were shooting larger arrows and get the same or more penetration with my axis in 3-d targets, block targets, etc. I was convinced. Smaller diameter penetrates better. I've heard people say that you can't judge by a target but maybe I'm dumb but to me if it's getting better penetration in a tight target why wouldn't this be true in live game???
Now I'm shooting my 400 grain axis side by side with these 366gr VAP's and they consistently went considerably deeper in the target. If these arrows weighed the same the results would probably be greater. Wouldn't this mean they are hitting harder and penetrating better?
Anyway I'm just starting to mess around with these but so far so good. You asked about size. They are really, really small. They are extremely tough though. There is a little problem with the size though. I may need to find a new or modify my quiver some how. They are considerably smaller than axis, beamans, and gold tips new kinetics.
IMO a higher Front of Center (FOC) is better for hunting also. This allows the broadhead to steer the shaft, causing less winddrift, and a harder hitting arrow with a lot of weight up front. That's why these inserts they have are neat you can get two sizes. I chose the larger 43gr insert that tapers out to 5/16th. This gives you great front of center and lines up with broadhead nicely.
Your gold tips are likely not a terribly heavy arrow (depending on your arrow length and spine). You could probably shave a few grains off your arrow if you want more speed but if your happy with your speed now I wouldn't bother and would try to keep them the same weight.
Should you switch?? That's tough I could probably answer that next december but now the verdict is still out. My main concern is the durability of the insert/outsert and the shaft itself. Will I be able to shoot multiple deer with one arrow. Which really depends a lot on the shot I guess.
Here's a little promo video for VAP's
http://www.youtube.com/watch?v=J7CfIGmX-u8