The #207 takes a lot of upper tension to pull the knot into the leather for a nice looking stitch that's why the next size smaller thread in the bobbin makes it look better.On the larger machines like the CB3200,3500,4500 with the shuttle system & 2-upper tensions works better w/larger thread top & bottom as long as your leather is thick enough for it.
Sight unseen is hard to price,condition of the table ,if the machine sews or not,so with that in mind from $150.00 - $450.00,try FB marketplace or Craiglist.
Yeah,alot of times it hides in there,if you leave the hook in there & just take out the 2-little screws on the ring that hold the bobbincase in it might prevent you from taking the whole hook out.
These old Landis #1 are great for heavy & thick material because the only needle made anymore is a size #26 for #346 thread.The needlebar is not adjustable so the only other needle that would work would have to be a longer one you could shorten.If I remember correctly it's around 3" long.Parts for it will be hard to find too.If you do buy it I know where you can order needles from.
Might just be thread jammed in the hook,put some oil all the way around the outside of the bobbincase & spin the shaft back & forth & it should free up.
This issue has been resolved.He brought it back to us & since he had a Ferdco 440 for some unknown reason he thought the top tension should be as tight as the Ferdco .So we adjusted the top tension (loosened it a lot) for him & he sewed on a lot of leather & was so happy he bought a CB3200 for his holsters.
Looping underneath is always upper thread either too loose or incorrectly threaded,with a home machine you could be using a thread to large for it can also cause looping.So double check the threading & then keep tighten the top needle tension as far as you need to get it to stop looping.