Originally Posted by MichaelW

Cheap aluminium racks work fine as long as they have sufficient struts. Yours looks fine.
Personally I don't like adjustable height racks, that is an unnecessary complication for the convenience of the retailer. The upper stays to the frame also seem to have a not very rigid connection to the rack body but it should suffice.
55lbs is is quite high load, the classic Blackburn EX1 is rated for 40lbs and for years was the standard expedition touring rack.