Bomo, the 1998 model I have does not have a drink holder as you're showing.
My suggestion, as this appears to be below the throttle/fuel sniffer system, is to enter from forward and aft both. You should be able to remove a cover panel at the bulkhead inside the hold beneath the helm (that's a mouthful). So - stick your head inside the hold under the helm. Look in the back right corner. There should be a removable carpeted "cover" vertically located covering an access-way to the stern. Be careful as this cover likely is thin plywood covered by carpeting, which may be hiding a screw or two. Remove the cover, slither into the hold as best you can and with one arm, you should be able to reach in and at least put a wrench or screwdriver on the forward T-nuts. To get to the aft nuts, remove the speaker (assuming you have one mounted where mine is located in the picture above). You'll be able to reach some of the aft nuts that way I would think. Bring help. You'll need someone for the forward nuts at minimum.
Now, if someone knows how to get the darned throttle/engine control off...... Haven't been brave enough for that yet. Don't really need to yet either, thankfully.