To answer the original question, the base circle is irrelevant. Get the cam with the specs that you need for your engine combination.
Lobe lift is the difference between the lobe peak and the base circle. Lobe peak is limited by the diameter of the cam bearing journals (the lobe needs to pass through the cam bearings when installed in the block). If you need more lobe lift than you can get by increasing the lobe peak, the only alternative is to go to a smaller base circle to increase the difference between the two.
The only downside to a reduced base circle cam is that you may need longer pushrods to compensate.