Weddingbee boards

I am about to buy some candles for my centerpieces..well, as part of my CP. So, I went to quickcandles but now I think the votives are really really small. I am planning on putting at least 4 per table and I've been collecting glass vases for a while like these My questions are:

1. Is it okay to buy these kind of candles to put in them? I can't afford to have handpoured wax :(
2. Do you think these candles are too small? I don't want pillar candles but they are the next size up. Of course if anyone has candles to spare I'd buy them :)
3. What should I put at the base of the glasses? Sand? Stones? I'm confused.
4. When should I buy the candles? Nearer my date or should I buy it now and get it out of the way?

  I guess I should go start googling coupon codes. Thanks.

I think using the votive candles are fine, but you will need some type of filler. I think the pearl drops, shown here, would magnify your candlelight, especially since everything you are using is clear glass. I think you can get them in different colors so maybe you can match your wedding colors. 

If I were you, I would buy them as soon as you decide what you want and get it out of the way.