A third print sold on eBay for $3800.00 back in December, but it was not nearly as nice, and it wasn't signed. A second print in as good a condition as yours, but not signed, sold for $14,100.00 back in December! A third print in pretty good condition sold for $4351.00 back in September on eBay, but it wasn't signed. A third print in "used" condition sold for $3,547.25 back in June on eBay. A third print set sold for $6,700.00 back in April of 2020 on eBay, and it was close to your set in condition, very fine + to near mint, but it wasn't signed. A third print set in very fine condition (or so) sold for $5,110.00 back in March of 2020 on eBay, and it was not signed.
Signatures on collectibles overall are a plus for some buyers and not for other buyers. I would say that these signatures are tastefully placed and add to the value, but not a whole lot. I would not be surprised if you get $11,000.00 for this set, maybe more. Patience is your friend. You will get offers. And while selling off eBay eliminates their fees, the number and range of buyers almost always results in you getting more money for your items there. Prices on items like these have jumped noticeably over the past couple of years making appraisals challenging. There are better appraisers on these forums than me.
WOW!!

Truth is worth finding and life is too short to work for money.