I've used the following for demonstrations that span the course of a day or weekend, especially when weather is a factor:
1) Beeswax...rub over the bow, then gently warm over heat source (I like a fire reduced to coals). The wax will almost instantaneously melt, allowing you to rub it into the wood.
2) SnoSeal...it's a leather footwear waterproofing product. It's mostly beeswax, but contains some silicone.
3) Paste wax, followed by some Birchwood-Casey Gunstock Wax
4) Mink Oil
I like option best in the order they are listed for this type of application/situation. Hope this helps!