Questions / opinions. I got the cabelas gift card ,christmas,went to bass pro,got the navionics east chip.i called humminbird prior to purchase.they said upload new software onto the 998 c hd di/si and the 798 ci hd di si before uploading the navionics.i purchased as a leg up for new resevoirs in Tn.the chip has the drawdown capability for depth offset etc. .my biggest questions are 1) split screen in a side find mode looks fairly simple.??? Dont want to waste a lot of time initially learning the capabilities when i could be fishing.2)talking to the guys on Tn Anglers , the overall preference for fishing ,not navigation,the most thumbs up seem to lean towards the navionics..aparently i need to purchase a 32 kb max sd card to upload updates from humminbird,the tech said to large of a card could cause issues.opinions,advice???