Well, all you have to do is look at the bid/ask spread prices...usually there is a number in parenthesis that says how many are Bids and how many are Asks. That's where you will get your general fill, before you move that price/quantity up or down, depending on how large the order was placed. The volume indicator displays the opening/closing quantity of contracts traded for the day. In general, you shouldn't worry about moving the market...if you trade the broad market SPY/SPX/ES. These are all huge. All brokers and market makers can accommodate and handle and process your order fluidly.
you better start reading some options books if you keep asking those kinda questions ... volume is what's being traded that day, volume on bid and ask is what you can potentially trade, open intrest is all the contracts that remained open the day before.
You will not know until you try, In general, if you are not taking offers and hitting bids and want to play in the middle or work your order, you have to find liquidity. you can expect the OTM options will find more size that ITM.
you can do 100 at least, even without looking at the prices on a sidenote: try to pose more intelligent questions ! ! !
A few thousand OTC.. Shit... you don't even know what volume is? Are you serious? ES is one of the most liquid products in the world... and you're wondering if you get into liquidity problems with your 4 or 10 lots?