The maximum fast ram on an A500 is 8 mb. If I were you, I would max out the HD+ memory and get rid off the expansion slot memory. Then you may consider upgrading chip mem.
The FFS which comes with kick 1.3 is not very friendly with large HDDs / partitions. I remember having a really hard time getting a 1gb drive to work with both an A590 and Gvp HD+ and finally giving up. It worked a treat with kick 3.1. Just my two yens.
