Reich weight gauge

Does anyone use one of these for weighing your caravan?  If so, any thoughts?  Do you use the yellow one or the orange one?

Will all the problems of overloading and dropped axles (including ours), I'm thinking I might invest in one of these gadgets.  Caravan goes in next week to have the axle replaced 'as a measure of goodwill' (that's what Bailey are calling these replacements).  I just want the easiest/ most accurate method of keeping within the specified weight.

David