What to do...

I didn't see the question - might have done if you'd put it in the Oil section, but things can get lost wherever they go...... I will attempt to address your original questions first! Number one - oil painting paper; yes, I use it for sketches, try-outs, colour-mix experiments. The only reason to avoid it is the question of longevity; but if it were mounted on a rigid surface, it should long outlive your grandchildren. You can get various surfaces and makes - use it just with oils, or alkyds. Number two - interesting question, and the short answer is No - not specifically. Thing about grisaille is that it's usually employed to be painted over in glazes; not all blacks - especially Ivory - are good for that, because they're ground in too much oil. I'll look out for grisaille paints, but in the meantime suggest you mix up Burnt Umber with a quantity of Ultramarine (other blues will turn the result to a deep green), or a mix of Viridian with Burnt Sienna, to make an optical black, and mix that with your white until you get the consistency and shade you want. Failing that, Mars Black or Payne's Grey will give you a good range of darks to produce a grisaille effect. Number three - Yes. Frequently ... even when I've done it before. The paper problem has yielded its own answer by your trying it, I see (second post). The turps - ah. Um. Normally, I would say don't use any Turps or other thinners at all if the stink is too much. It wouldn't be easy to get the gradation you've got in your picture, though, if you used no medium at all. There is no such thing as a healthy thinner - white spirit honks even more than turps; turps can appeal to some people - I rather like it - but not to many; and it's perhaps the least healthy option available. You could switch to Low Odour Thinners, made by the usual manufacturers, otherwise known as Sansodor - these won't stink the gaff out, but they're still hazardous and require proper ventilation. Or, you could use Liquin (I hate the smell, but it tends not to linger), or Zest-it, which has a citrus smell - I don't know how good it is for long-term paint stability ... there is much controversy. Or Winsor and Newton's or Daler-Rowney's Oil Painting Medium (much the same stuff, it'll have different branding names), or straight Linseed Oil - which has much to recommend it, but is, inevitably, well - oily. There are also gels - some of which allow more fluidity than others - I'm unable to offer any useful advice on these, because I haven't used them for a very long time. I hope this is of some use, even if it did take a while to reply.

Work is indeed required in this business - but that's a very good result you've got there, even if looking at it does make my back ache.