The stock TS tone filters on the feedback loop roll off the open 6th string by around 20%. The different cap values all sounded good with guitar, just different from stock. Going too high on the cap starts to get woolly and muddy though. So you are right, this is why most dirt pedals filter extreme highs and lows in the gain stages (to avoid mud and/or grating upper harmonics and fizz). It is nice to have different sonic options on tap at the flick of a switch though.