Cops do not generally ask you to hand over your firearm for officer safety - they tell you they are going to take it from you. This is not a common occurrance, but if it happens you have a few choices.
Shorten your response to something along the likes of "I do not consent but will not resist." It's easier to remember and you may get it all said before the cop tells you to stop talking.
Keep your hands away from your firearm & holster at all times once the cop(s) have indicated they are interested in you and your activity.
You can, if you like, offer to instruct them on how your holster works. Be polite and not condescending. Keep your hands away from your holster and firearm. Do not point. Do not turn or twist. (Suggestions from me to you. No rules that I know of regarding this.)
While there is no legal requirement that I know of to actually hand it over, there are, as you can imagine, a lot of good reasons not to oppose the taking of the weapon while there in the middle of the event. That's what attorneys and courts, and formal written complaints, are for.
If, on the other hand, the cop asks you to take the firearm out of the holster, I'd politely decline and state that it is safer staying there without anybody handling it. Again, keep your hands away from it while having this discussion.
While arms folded across the chest are usually seen as an aggressive/angry gesture, it is an option that puts your hands away from your holster. Interlacing your fingers (folding your hands) and holding them in front of you at bellybuton height may be seen as somewhat less aggressive. Putting your hands up in the air or on your head is probably going a bit too far unless specifically directed to do so.
If you have not yet joined VCDL www.vcdl.org consider doing so, or at least signing up for the free email newsletter. Go talk to the VCDL volunteers who are at the local gunshows, and also find out about some OC events near you so you can talk with folks who may have more experiences than you do. (Remember that we are fukk of advice among other things, but the answers are not guaranteed to either cover all circumstances or even be "correct". Check for yourself and make your own decisions.)
Oh, yeah! A digital voice recorder (so a search for recommendations/reports) never is a bad investment.
Welcome to the world of firearms ownership and OCing.