An update, of sorts...
Still haven't had a chance to play tin basher - maybe once the weather goes to pot. I have been searching on and off for a distributor/gunsmith/gun store that can get that Savage sear (part #103871). Western Gun Parts had them for a short time; but apparently it takes 6+ months to get parts from Savage... Anyway, latest news from another gunsmith is that, according to Savage, the part has either been discontinued or is no longer available for sale (most likely the latter).
SO, once again, if you want to convert your bottom bolt release Savage to a top bolt release; you'll have to play gunsmith/tin basher. Or, maybe you can get the part... somewhere?
I had this issue a couple of years back (bolt release was actually busted IIRC) and went as far as taking my rifle to a gunsmith who still couldn't get it from Savage Canada (Stoeger IIRC?) even though he was going to do the work. In the end I said #### it and bought an MDT chassis. I had also previously tried a PTG bottom metal which was the correct spacing to fit the 10TR, but it would have required a LOT of fitting to make it work. Bighorn can get the PTG stuff if you want to try that route. Lot's of screwing around for zero benefit beyond cost. The MDT chassis was excellent and worth every penny.