I'd be happy with that shot of yours
I really want to get back to the old film IR 'glow' effect so ultimate sharpness doesn't concern me too much but I'll be honest - I'm completely new to this and am just taking my first steps on the IR learning curve. The completely unhelpful answer is that I don't know how sharpness compares between using a filter or a converted body, sorry
The reason I'm converting a body rather than using a filter is mostly because I want to be able to use the viewfinder and compose shots normally rather than long exposures/tripods etc.
My pic was at 2.8 - pixel peeping I can't see one thing in focus though which would suggest to me I've either got a layer of crud on the filter and/or sensor or I need to have a look at the lens calibration. At infinity I didn't think the wavelength difference between IR and daylight should make any/much difference but I've not thought it through so may be talking cack - too late in the day for giving myself a headache so it'll wait until the morning...