you should still be able to see the mark on the flywheel and line it up to the window. look for a mark on the cam sprocket and that should be close to lining up with the spray bar. use the fly wheel mark first though if you use the other mark you could be off by 180. both valves on the 1 cylinder should be closed when your tdc. if you pull your plugs out you can probably rotate the crank shaft pully by hand.
when i removed my head, i didn't set to tdc, i did mark one link on the chain and a corresponding mark on the sprocket (i used some degreaser than white tremclad with a q-tip), and use a screw driver through the chain and some zip ties so it didn't go back in and slip the crank sprocket. cam sprocket only ones on one way so you dont have to worry about markig the cam. pull your tentioner out too, give you some slack to work with. do check it all your marks when you get it back tother though, triple check once the distributor is back in and you turn the key. to make life easier, you can put the distributer housing back on before putting the head back on engine (but not the distribtor). do whatever you can to avoid loosing bolts into the engine, jam rags in wholes, tape holes, make sure you have a magnet on a stick. remember to oil the tentioner when you put is all back tother too (once its back in the engine, pour oil into the top of it, youll see a little ledge kind of spot)