Scanning slides on a flatbed scanner

[Kenneth]

I have recently given up print film (lousy quality at high costs) and have started taking slides again. My flatbed scanner, an EPSON 1650 Perfection, has an adapter and lighting unit for scanning slides, but I am not happy with the results. If I scan about 300-600 dpi a slight blur amd loss of detail always remains, if I scan at several thousand dpi I end up with a slightly better 30-40 Mb (!) file which is cumbersome to handle. I know that I am not likely to produce scans this way which will make it into this or the other site, but any hints to obtaining better scans this way would nonetheless be much appreciated (e.g. which dpi and which zoom factor; it always seems to set the zoom at 486% automatically).

Thanks in advance,
Kenneth