[LAD] precision resampling to correct clock differences - no luck with libsamplerate and zita-resampler...

hi *! i need to re-synchronize two recordings of the same event that for technical reasons had to be done with unsynchronized clocks. i'm assuming for the sake of sanity that both clocks were perfectly stable. my approach is this: in ardour, align some unique feature (a click in this case) at the very beginning of the recordings to within a few samples. set a mark1. then, identify another unique feature close to the end, set mark2 to its position in the reference clock file and mark3 in the file that needs to be resampled. read the frame positions or the markers from session.ardour. sample rate ratio is then (mark2 - mark1) / (mark3 - mark1). i compute a value of precisely 1.00020678091, and i'm now looking for a resampler that will do the right thing here. unfortunately, both zita-resampler and libsamplerate seem to represent the sample rate ratio internally as a fraction of two integers, which means that in my case, it will be rounded to 44100/44107. this is not acceptable for the usecase at hand, as the offset after 4 hours of recording would be too large. due to the massive amount of data to be processed, slicing the material into smaller chunks to reduce the error is not an option. is there a hard technical reason for the behaviour of the resamplers? would it make sense for this bear of very little brain to dig into the code and try to convince them to perform resampling at ratios with full double precision, or is such an undertaking bound to fail? thanks, jörn