I went a little larger than just spectator chairs. Since I have a "few" friends that play here at the house from time to time, I found an old church pew and built a 12" tall riser to set it on. Riser is carpeted and trimmed out and the pew is bolted to the riser. I'm still going to build arms for the ends with drink holders and cue holders, plus a console in the center to do the same things, but for now, it gives everyone here a place to sit and a great view of the table.
Keep in mind, I have a LOT of room in my game room. The area where the table sits is 25ft X 25ft, so a riser like this wasn't an issue as far as space taken.
Bob