It used to be that slingerleedy's would go for the same amount as a like Slingerland kit,last couple of sales I saw looked like they went for a bit more,say 15 per cent.
The Slingerleedys don't command prices like the originals. I have seen a few 60's era slingerleedy's and liked them a lot.
The six lug snares are great Blues/shuffle drums IMO, but are not commanding a lot of money,I don't think.Just like Sling 6 luggers.
Finding a matching 14 or 16 is probably not going to be easy,but you could find a blue glass glitter slingy FT to use while you are looking.
Since the ft would be so hard to find and the snare is not worth a lot,I would say 600.00 to 700.00 tops if they are all original and in good shape.
Good luck and I hope you get them,I really dig those Leedy lugs.