8 in a van is very comfortable size. van holds 14 people so you all get a window. also a VERY good price break at that level. we just got back and we were sooo happy we did the smaller private van so we could plan our own itinerary and get in and out of places faster so could see more. tell them you don't want to waste a lot of time on lunch. the fast food blini and pirogi places were great. and real Russians were eating there. and it was quick and cheap.
some people even brought sandwiches from the shp. and others had box lunches delivered to the van for them so they could eat on the move. they were able to fit in Catherine's palace on top of all the ship's tour places.
the canal trip is nice but i think it is missable. you see everything in the van during the day thru large windows that you see on the river cruise. it was a nice float down the river BUT i had that sense of "what am I missing out there in St Petersburg". i'd rather have spent an extra hour in the Hermitage myself. we added a quick stop (15 min) at the Synagogue. they have to call ahead for you to get in so let them know in advance you want to stop. it's right on the way to/from the ship. I also think we spent too much time at Peterhof. after a while, another tulip looked just like the last tulip and another all gold room looked just like the last one ha ha. i was surprised that shopping opportunites were not that great. didn't want to spend a lot of time on it but there was so little in the way of choices that we just got one set of mandatory dolls and 1 christmas ornament. by the way, the swarms of vendors outside the Hermitage had the best prices. 3 doll sets for $10!!! and I liked a lot of their original artwork.
have a great time. rest up. it's an exhausting itinerary on this cruise and you lose ANOTHER two hours of sleep between Copenhagen and St Petersburg. be sure to be down to the gangway reallly early so you can be first ones to get off the ship, especially in St Petersburg and Stockholm. you need to beat the tours down those stairs. i'd say be down there by 6:20am. really. it all went very smoothly. there was NO question or problem AT ALL getting off the ship with no visa. your tour guide will be waiting for you to the left side as you get off.