Kelly,
Three in one may work for simple machines, but if you get into ZZs or one with cams, It can gum them up pretty easily. I only use sewing machine oil on my lovelies' ( I buy it by the gallon).
My GF is the sewist and she does fashion.
https://www.quiltingboard.com/member...163-613393.jpg
I have done a few minor projects just to get familiar with the machines. I've been a gearhead all my life and when my GF's featherweight acted up on her, she asked me to fix it. I'd never touched a machine before, but after reading the manual, watching youtube and much encouragement. I got it running again after several tries. Now I treat them like 3 D jigsaw puzzles. I'll buy poor ones, and bring them back to life ( usually) . We just had 12 of them in a museum in a temp visit. I keep thinking one day we'll contact the Macaffee (sp?) stage coach area and demo there. Haven't done that yet. I give them away or sell them when I am so inclined. Not making any profit.
Glad your wheel is there. Did you think to oil the treadle itself. It can make a lot of difference.
I consider a 66 or 99 oiled well when I can give a quick flip to the handwheel and it will spin 3 revolutions.
Have fun.
Oh, and yes Iris (GF) will sometimes use my old beasties. Mostly when her new machines balk at too many layers. Ha!