The original set-up, with the fiddle blocks, was (is) a 4:1. There is no difference in effort between the in-line vs the side-by-side blocks. The main advantage of the side-by-side blocks is the stack height reduction, which allows more mast rake.
The most important components of the mainsheet are the lower block (with the cleat) and the line itself.
There's a Harken system on eBay right now for $226 - http://www.ebay.com/itm/Harken-6-1-Low- ... 288wt_1159
Use the rest of your money to replace the crappy line that's on that system with some New England Ropes Salsa.