To avoid problems with condensation in the future, the importance of *perfect* sealing cannot be overstated!
Glass shops use a special type of sealant for double pane residential windows. It remains very pliable & is intended for this type of application (hermetic sealing). I also recall someone once mentioning putting some desiccant beads inside as well. Flushing with argon or nitrogen may be a bit of overkill, but if you’re into that sort of thing…