How To Prevent Tuff Coat From Streaking?

[rmr]

Have been placing a veeeeery light coat of tuff-coat from weaver Leather on some leather steelhead/salmon fly wallets I have recently made. Been applying it with a damp sponge and what I feel is a very light coat. Sometimes it comes out fine and other times I get streaks. Would like some recommendations of what I should be ( or not be) doing to prevent this - and / or how others apply this product

Thanks RMR