What I did was use the rotary to cut the height of the grass lower, then gradually lower the height of the cylinder mower until the grass was at the desired height. One thing is for sure, cylinder mowers do not like long grass particularly if it is wet. As far as a scarifier, I have never used one so I couldn't really offer any guidance on that one. I think if you take the gradual option as i did you will get there. When I cut mine I run the mower over the grass twice, once because I enjoy cutting it and also the second cut seems to keep the grass flatter and lower. Every now and then i cut lengthways as opposed to side to side, this keeps the lumps and bumps away. Ideally to keep the defined lines looking really nice it should be cut every 2 or 3 days, but i don't get the time during the week. Why dont you take a couple of pics of your grass so we can get an idea of where you are at and don't forget to have the reel and the bottom blade sharpened - there is plenty of info on how to adjust the reel correctly, just check out Deejays posts, especially the vids.
Hope the above info helps.
Cheers ,
Ross