I am sure you are aware of what I am about to say, although I question some of your reasoning. Perhaps I'm not getting the whole story.
1) On your first attempt, of course the bead would not set without rim strips or rim tape. Spoke holes can't seal themselves. There are only a few wheels in the marketplace that don't have spoke holes drilled into the rim, so a rim strip or rim tape is a necessary item.
2) Your wheels are not UST, this means you will need a liquid sealant such as Stan's or Orange Sealant (my personal preference) to seal the bead, possibly around the stems, and anywhere the rim tape didn't do the job.
3) Gorilla Tape is a common alternative to Stan's rim tape, if you have the correct width of tape for your rim width, you should have good luck using Gorilla tape. If the tape is too wide, it will interfere with the seal between the tire and the rim.
4) Yes, add your tire sealant, shake the wheel like is shown in the Stan's video and get your tire to seal well. A good seal will not lose air for a week or so, however, this depends on the tire as well. Thicker rubber will not lose air as quickly.
Good luck finishing your build, I'm glad someone is still choosing the IP-057 as it seems everyone is liking the IP-256 lately.