You need to find someone who can do it for you? I assume the current oscillator is soldered in, then?
In that case I would definately recommend you order yourself a 14-pin DIL socket to go in there. All you need to do is cut off the excess pins, leaving four outer pins and it'll drop straight in place on the board. That will give you the opportunity of putting any oscillator you want in there at any time, which of course is a massive advantage.
In my travels earlier I found a website where a guy had overclocked his 50Mhz version to 66Mhz and according to him it works perfectly, so you could even try an even higher oscillator in there!
The job itself, fitting a socket in place of the oscilator, is not a hard one especially on your board. If you're living anywhere near SWAUG (South Wales Amiga User Group) and you're wlling to bring your system down for us to look at, I'll even do the job for you myself.
Other than that, contact a local user group to you and see if anyone there has soldering skills.
Best regards,
Brian