I would get all the pieces ready for final assembly, including the wax seal
and the hold-down bolts. I would then use copious amounts of silicone rub
ber on everything in sight, except the wax seal itself. I would even put s
ilicone rubber around the perimeter of the wax seal, so that once the rubbe
r cured, there would be no way for any moisture to escape from the pipe con
glomeration. I would then bolt the toilet down, maybe within 1/8 inch of t
otally bolted down, and then leave things alone for 24 hours. I would then
finish tightening the hold-down bolts. Short of a 300 pound person rockin
g the toilet, or an earthquake, yuou should have a fine installation.
For extra insurance, you could also run a bead of silicone rubber around th
e perimeter of the base of the toilet. Since it is on a slab, there is no
danger of any escaped moisture rotting the floorboards.