Use this link instead. It has a property look up feature and one can put in three PIN numbers and pull them all up side by side. let me know if you are already working with an agent, I would be happy to be of assistance. Round lake is higher on a cost per thousand basis than Grayslake. there are some nice areas unincorporated lake county that have relatively cheaper taxes.
A local realtor can tell you the estimated property taxes for specific homes from the MLS listings.