Welcome aboard. You would want to run your mower at 540rpm. Most folks achieve that by putting your pto in 1st gear and running your engine around 2200rpm. I believe your 1st speed (540) is with the lever down. Somebody correct me if I have it wrong. I beleive your speeds are 547, 709, 929, 1232 with engine around 2200. I am not positive on this but doubt it will be far off. You need an over run clutch for your mower if you don't have one. You could run your engine at 1676rpm in 2nd pto range to achieve 540 mower rpm. Just be careful not to lug your engine.
There are numerous parts dealers that frequent this forum. Hoye has an ad at the top of the page. You can google and pick up more. They sell the manuals and you can sometimes get them on ebay.