Colocation contributes maybe only 30% of trading volumes on exchange.
As a retail trader, I think the best thing to do is place the order at the market open. There is no pre-market session for F&O. Btw trying to get this first few ticks of the day is luck of the draw. Also, there could be stray ticks that can cause you large losses. The best thing to do is wait for a minute and then place your order.
Yeah, wait for the market to settle down and then place an order. On certain days you might want to enter or exit at open because you feel market can go up or down due to some overnight news, but remember what you know everyone else knows as well. If there are a bunch of people trying to enter and exit right at the open there can be stray trades way away from actual market price.