But again thats me. I have a 600 mm allihin condenser just for that as it really gets hot, boiling! I would be scared the boiling methanol would just flow out of the top of the condenser. It really refluxes hard, and if you put in too much nitro when trying to drip at the proper pace and you will have a volcano with methanol spitting out!
I dont think it can work, unless the addition is extremely slow, your flask in on ice to keep it as cool as posible.
But again, I wonder about the amount of foil you would need to use to keep the nitro addition slow.
If this is your first time, and you cant buy another condenser(either a longer one, or the same but staked on top of your first one) then I wouldnt try to transform 25 g of the ketone. It will get way too hot when you drip the nitro in.
Of course this represents my own opinion and experience, and I have run many nitros before I decided I was much better off synthesizing MeAm as a salt first Still if I run a reduction with it, I use my 600 condenser
Hope this helps, let us know of the results