I have been considering this website as my family emigrated from there in about 1850s. The pay-per-view has made me quite hesitant to try it for the very reason you mention - getting too many random returns to view before being able to find any relevant ones. Could I ask, how many files were you able to view for those 90 credits, and how far back were you able to find documents for? Unfortunately, I live too far away for a trip to the Glasgow Library.