Going to lighter wheels saves both on actual weight and, more important, rolling weight. The freewheel is also heavy.

My advice is to buy new wheels with a freehub and get a 7-speed cassette. You should be able to operate it in friction mode. IMHO, the best buy on lighter road wheels are the Performance Titans, which weigh together about 1,750 gms and can be found on sale for about $150/pr. I have a couple of sets of Titans and have put thousands of miles on them without any problem or maintenance. On the road forum, the Titans get grudgingly (because they are Performance) rave reviews.