If you think you will use it often and the money is not too much of a stretch, then go for it! Innova has a great rep and the 26" vs 22" is not an issue if you can not reach the back of a 26" (my Gammill is that lenght and it is a stretch!). I hear what you have said about taking it apart yourself--I was nervous buying my Gammill used and felt such relief when an area tech was able to meet me at the sellers house and once I purchased, brought it to my house and set it up. KNow others have said they don't use several of the features--but the Towa gauge has saved me so much headache once I figured out how to use it, and I use the horizonal channel lock when I attach a quilt to start (rarely other than that), and the seperate bobbin winding is a must! Wish I had the electric advance, and I love the stitch regulator--have heard good stuff about the Lightening system Innova uses.
As far as health--if your's is good now, don't use that as reason not to purchase if you want and will use it--ANYone could have a health problem suddenly! And while standing is certainly important, I have found that I can use my drafting stool for much of the work that isn't edge to edge. You might want to ask if the seller will throw in the rulers and thread she has for this price, too!