I am abou to start filleting my chesse 16. I measured from bow and stern 4 ft and used a level. Both ends show that they are level. I also "eyed the sides and they appear smooth with no bulges, etc? Is there anything else I should do before starting to fillet. Also, I have the kayake clamped just under the sheer clamps. How long can it stay in this position without doing damage to my kayak? Thanks in advance for your input.