Looking at 999 with SI. Concerned it might be to advanced for a novice on a fishfinder. Hoping will help spot crappie and bass. Will b fishing relatively shallow 8-10 ft muddy lakes for crappie and my home lake is Lewis Smith Lake. Very deep clear water and fish for bass n strippers mostly here. Also does the 999's maps cover this lake with underwater contours etc not just outline of the lake. Thanks for your offer of help.