In the mean time, while you are leveling....look into some of the quick Resistance Ops in the Bastion zones if you are in those areas (some only take seconds to do, and offer a chance for seals--can run one while party is gathering and such). When getting XP in the Dominon areas, you'll be spamming pages for the bonus xp, which also grants a chance for seals. So, you may find you knock out some of your seals along the way.