Hi, there is probably no need to alter the lie of an old putter to get an idea of whether the "Symple System" will suit you or not.
Let me say this-if you like the idea of the "symple" method with your current putter/s you will absolutely enjoy the "scoring machine putter". This putter is very cleverly and precisely engineered for the purpose that Mike & Joe intended.
Go ahead and buy it- there is nothing else available that comes even close to the "Symple".
Even if you decide not to go with the symple putting method the putter in itself is still a very good weapon of choice for a variety of putting styles.
I'd say try the method with your current putter as is. Now Symple Putting does work better with some putters than others. The more upright the putter the less effective it is.
That say you should be able to get a good feel for the potential of the system just by trying it with your current putter.