I found this 6" actuator at Everestpart Supplies. They also have 4" and 12". I think from what I've read 6" should be ok. Any advise?
http://www.everestpartssupplies.com/products/new-heavy-duty-linear-actuator-6-inch-stroke-225-pound-max-lift-dc-12v-12-volt Paul Visk Belleville Il. 618-406-4705