Don't get 100% caught up on the whole leveling thing! So many of my customers worry about leveling and then time and time again come back with questions about how to achieve high speed readings or amazing images....
Leveling your transducer is a great starting point but being 100% level is not needed in order to achieve great images. I typically am always kicking the back end of my transducers or customers higher than level (remembering with ever change in angle, you will also have to compensate for the height change in the leading edge of the transducer! I also tell my customers to ALWAYS setup your transducer for how you use your boat the most and for how you want to achieve the best images. To me, high speed readings (Marking not only depth at speed but fish/bait) is absolute huge and the most important for me! At 2mph trolling speed a transducer that is not parallel to the water surface (level) is still going to have great images so I concentrate for where I need it to be perfect...and thats at speed! Also, many assume that un-even arch's are caused from the transducer not being level...all though this can be the case if severely angled, its simply not true in most cases. 99% of the time, un-even arches are caused from fish that are on the very edge of the coneangle. If you ever are trolling a long and see your entire screen loaded with severely angled arches (sometimes straight lines on a 45d angle...it simply means that those fish were all on the outer edge of the cone angle and not directly under the boat. Only fish that pass directly under the transducer will have perfect arch's. For high speed running I also make sure A-Scope is turned on (lowrance) which gives me instant real time data telling me I am passing over targets (remember anything you see on 2D sonar already happened and is now history....nothing is current!). A-Scope and Live Sonar (LiveScope, ActiveTarget are 100% real time and happening before you eye's). At high speed fish no longer look like arches but usually just DOT's which can be confusing to some but once you know what you are looking for its an absolute game changer.
Hope that helps...Ryan