In this case, if it were me, i'd be running premix anyway. Had one of those express oil injectors bail on me, and aftermonths of being just fine. As for the window, your best bet might be creative engineering. find some oil safe glue and gob in a new window. I don't think those were ever intended to be replaceable so I doubt replacements exist, and even if they did it's not likely they'd be any easier or more reliable to get in than just gluing on a new window.