I dry fitted the tanktop, then traced a line off of it to the inside of the strake. Remove the the tanktop and use the line as a reference for positioning the cleat. No need to "pile on the thickened epoxy". Use just enough to get the job done. You are going to fillet the top of tanktop anyway which gives plenty of strength. I didn't find it to be a particularly tricky assembly. Good luck. 

Thanks for the advice.  I'm probably making this step more complicated than necessary, but the difficulty seems to be fitting the cleat while dealing with a compound curve (the curve  of the strakes as the hull tapers to the keel and as they come together towards the stem); I'll simply forge ahead.  I've had a good look at your build photos and videos throughout my build and have drawn a great deal of inspiration from them in addition to using them as an invaluable reference tool.  Your boat turned out beautifully.  Thanks again.