Are you running the report from a query? If so, you could enter >0 in the criteria for the weight field. This would take out all the records that are showing as 0
Have you tried ticking the "can shrink" box in the properties on the "Detail" section - that will stop the report leaving spaces where there are blank fields
I am based in Oxfordshire and do a lot of work with databases and spreadsheets.
I find this site really useful to solve problems and often find that I know the answer to posted queries, so thought I should join in formally.