I may not be much help because I haaaaaaaaaaaaaaate acrylic paint.
BUT I do have experience with both media. Overall, whether you will need to learn a whole new way depends on your technique. There could be subtle or enormous differences. If you prefer glazing, then the differences will be less than if you prefer impasto. 'Fat(=more oil) over lean(=less oil)' applies to oils (making each successive layer you add 'fatter' by mixing in more linseed than in previous layers so that the paint on top takes longer to cure than the paint underneath, so that the top layers don't crack as the whole thing cures), and oils stay 'wet' longer, so these affect how you paint as well. I used a quick-dry medium once and I don't know how effective it was because I abandoned the painting.
Oils, whether water mixable or not, require ground preparation, little of which is necessary for working in acrylic.
My usual medium is gouache/ink/watercolour, but I am also thinking of getting back to oils for similar reasons to yours. I love the texture of the water mixables, and there's just no way I could cope with turps for traditional oils, and I also find that acrylics hurt my airways and cause swelling. The wm oils smell like linseed oil, which to my olfactory sense, is far preferable to acrylic emulsion, but it is definitely different. I still needed ventilation though because it still filled the air. I find the same with gun arabic sometimes too, and it's
edible...
If you are not spraying them, wm oils are less toxic than acrylic because they are just pigment+linseed oil (chemically changed to accept water). Winsor Newton has a decent overview of wm oils
here. The toxicity of oils is mostly due to turpentine needed for cleaning, and of course certain pigments are toxic, but these are standard fare for paints- the cadmiums, cobalt, etc..., so in that way, oils are no different.
I used WN because they had the largest range and excellent quality, but if
M. Graham ever makes a water mixable oil, I would likely switch; their paints are fabulous (and they use walnut oil, which doesn't yellow and smells much better imo).
You'll have a learning curve for sure, but going from acrylic to oil couldn't be more stressful than from watercolour to acrylic, as a local artist here did. Now
that is a big switch!
And, btw, I don't care what anybody says, there is no shame in receiving remuneration for your art. Making art is real work. Not only that, but it's your life and if you want to support your life and further artistic pursuits by selling your art, then that's completely valid. Nobody is
entitled to your art; it's from your skill and labour that it exists, just like any other commodity, so if they want it, they can pay for it just like they do for milk and cars and movie tickets- without complaint. And if your art is more like creme brulee, mercedes benz and opera tickets, then they should expect to remunerate you in kind.
This site is awesome for the business end of things, in case you had not come across it before.
And
, you're making art!!!