I had pretty terrible problems using camelsystem powerpost. It sounds great because it supported more upload connections so I thought it would upload faster, which it did. Problem is it screws up all of the crc numbers so that none of your par's will work with the rar's that you upload. Perhaps it was user error but I've never had the problem since I stopped using camelsystem powerpost.
Yenc PowerPost has like 4 or 8 upload connections if I remember right and Camelsystem PowerPost has something like 12 or 16? Jbinup has unlimited connections so you can set it to 30 or 60 or however many your provider will allow you to use.
Jbinup does everything that all of the old outdated powerpost programs do and more. The fact that it has unlimited upload connections and SSL built-in makes it the single best choice that I've found so far. It is more modern and much more stable in my experience. I highly recommend ditching everything else and going with Jbinup.
As far as finding your stuff I'd probably just hit up a Newsgroup search engine and search for Team Blu in the NFO file or the actual title and see what pops up.
Multipar has several sizing schemes. It should be possible to make the par's the same size as the rar's. I've always used variable size which makes a few smaller par's that double in size for each step and then level out at the rar size. So the first few par's would for example be like 10MB, 20MB,40MB,80MB. Once it reaches the size of the rar's it levels out at this size and stays there which in our case would be 100 Megabytes.