[mnwnvc]

I also have a 69 CC. There is only 30 inches between the back of the console and the rear boxes. Not enough room for a leaning post or good seat with any room to run down riggers or fishing. I experimented with moving the console forward but it really messed up the lines(look) of the boat. I opted for no seat or post and sit on a fish box when needed. If your floor is stock it is also shaped to key into the console and moving it forward will require cutting the raised portion out and redoing the deck in that area. The boat really looks better with the console in the designed position. You have two choices, more room forward or more room aft. Use would be the deciding factor.
As far as your fuel tank I would leave it under the console. Less fabrication on your deck and real easy to replace. The is also a safety factor in having the tank above deck and it eliminates blowers and side vents. I set my boat to run off the tank under the console or 6 gallon poly tanks. That way I do not need to leave large quantities of fuel in the big tank unless needed. Good luck with your project. M