Make sure you have 3" min between handles when oars are level. This will prevent hand crushing blows
Usually you want to sore stuff under the rower (drybox or cooler). This puts you up a bit. Make sure your legs are straight enough to keep knees below your hips. If oars/seat/oarstand is all correct you should have oar handles a little below the chest during the stroke which should mean the handle can drop about 1 foot during the return stroke. With 1/3 inside and 2/3 outside this means the oars lift 2 feet. With 1/4 - 3/4 that's 3:1 so you shouldnt have problems with hitting your oars on your knees unless your geometry is all messed up
Hey, if you want me to take a dump in a box and mark it "guaranteed", I will. I got spare time.