You can elasticate an inline method feeder. Just tie some powergum onto the mainline then complete the setup as usual & check that the feeder will pass over the knot. This needs to be checked with fishery managers before use, some will regard it as free running & some won't - obviously not legal where knots above the feeder are banned.
The Guru elasticated method feeders have a tube with the elastic in it which will pull straight out of the feeder also the tube will fit the inline feeders as well, the elasticated tubes can be bought seperately.
It is probably best to invest in some ready elasticated feeders.
Then use a swivel with a snap link or quick change link on the main line. This way you can be baiting up one feeder while waiting for bites and speed up your fishing by just attaching the made up feeder when re-casting. Also you can use different hook/bait set-ups and find what is working best on the day.
Hooklength is attached to the ring at the bottom of the feeder.
snap link on the end of the your mainline, put the method feeder on, then at the ring at the bottom of the elastic have a quick change link covered with a bit of tubing, so you can change your hooklink quickly, thats how i do it anyway. i use the korda stik klips as the quick change links.