Why not try (borrow / rent / buy and return it to the store) an amp modeler to get an idea of the kind of sound you want then..... go for the real thing. I use Line 6's Pod however there are tones out there (Avoid the amp factory by Boss as it really sucks !). Many people criticize these things saying they are not as good as the original and that may or may not be true (Having never played a 69 Marshall Plexi ) however it will give you an idea of the sort of tones that are out there and a ball park idea of what to expect !