We did this when the "Jewel" was brand new in '04. No recollection as to whether or not they move the formal nights (which are usually second night and second from last). We used the ship's excursions for the simple stuff but St. Petersburg is a HUGE stop. We used "Red October" based on recommendations on the boards (in fact I think one was the ever popular "Kuki"). We had a private driver and guide for $100 more per day than the ship was charging to haul us around on a big bus. This may no longer be the case because they were really trying hard to expand their tour company.