Just reading Pascoes article and it seems to say to run the plastic strips across the width of the tank not length wise as I see in pictures of other installs. Is that right?

My opinion. If the cross members which the tank will sit on are let's say 4" wide and total five I would put five 4" wide plastic strips on the tank where the cross members are. That way the support goes side-to-side all the way edge to edge with the plastic strips matching the cross members.

My last tank was put in with this method and all the strips ended up coming loose from the tank and moving around. Was a complete mess. If you have a tank made up from thicker material it negates most all issues. Thicker material and foam or glass or whatever to keep it from moving and it will last longer than most of us will be boating.