only way to do it safely and legally is either the tracks that mount to the floor for using ratchet straps(way too invovled) or fastraps!! we use fastraps for all trailers and they are super awesome. 2x4s are a bad way to think your mowers are not going to move, small accident and they are flying around unless they are truly strapped in
all is fair in love and grass!
Man, it smells like sheet, do you smell that!!