I would stay with the hardi product. I think the quality and paintability is better/longer lasting. I have always used their lap siding instead of panels, but both are easy. The lap siding allows you to have all hidden nails and looks classier. You do not have to predrill the nail holes, in fact I usually use a nail gun. If your t1-11 isn't terrible leave it on as subsiding. It would have to be really bad not to be able to use it. I've never used the carbide blade to cut it, they make an electric shear, kind of on a hand drill that I've used exclusively to reside 10+ houses. very easy to use, no dust, doesn't get dull. In fact some bldg. suppliers where I live, if you buy the siding from them, they will let you use their shears for free. IMO use the lap siding which doesn's cost much more and then you don't have to deal with the nail heads. Also caulk as you go. Put a piece on, caulk the end and slap the next one on and wipe the excess off with a wet rag. I always cut two measuring jigs out of wood to hook under the 1 below to set the next on to get the lap exact and so forth. If you use the exact paint that hardi recommends they will guarantee the paint for 20 years I think. Goes on quick and looks great. Any questions just ask, good luck, bob