"Acryl Pro people advised me..." I'd follow the advice you get locally, except from big box stires where they now hire sales persons who have human relation skills instead of people who have experience in using the products.
Besides it seems that when someone here gives you advice, you're already a step past us.
I have no idea what "a heat resistance of more than 10lbs per tile" means either. Last time I weighed a fire my scale burnt up. From the sudden burst of flame, I'd say it was only rated for 3 pounds of heat. Or the fire could have been metric and incompatible with my scale.
[CENTER][FONT=Comic Sans MS]Measure twice, cut once.[/FONT][/CENTER]
[CENTER][FONT=Comic Sans MS]Look at the nail, not the hammer. Watch the fence, not the blade.[/FONT][/CENTER]
[CENTER][FONT=Comic Sans MS]If you hook your thumb over your belt you won't hit it with the hammer or leave it layin on the saw table.[/FONT][/CENTER]