RCM Floats scaled to 133%. Suitable for 90 or 120 size or other large planes.
An alternate version is available with a 1″ x 20 inch spine to take the place of the plywood brackets. This spine is to be glued on top of the float. Your landing gear axles are then attached with nylon straps, and wheel collars are added to each side of the plywood spine to keep the floats from sliding sideways.
These can be built without a plan. Attach the bulkheads to the float tops, using the laser etched marks as a guide. Add the sides and longerons, then the bottom sheeting.