not sure of GPA but FMV is about $1500 a point low grade so a 1.5 would be $2000-$2250 pending eye appeal, PQ, chipping, etc
Your pricing isn't that far off it appears:
One went for $2,550 recently on eBay - 2nd over $2,500 in grade this year in GPA.
Hulk 1 CGC 1.5 - SOLD on eBay for $2,550
Within 48 hours another one went up for sale at $2,500.
Hulk 1 CGC 1.5 - For Sale eBay
The guy with the brittle page Hulk 1 has listed that book off and on since April (for the same price). With the tape and PQ, I don't think he will be able to get that much though.