Hello there,
Myself Harisankar P S, i have three years experience in Ruby on Rails and have also worked with sphinx. After reading the task you mentioned in the document, i believe i can have it completed in 2 days time. The actual work won't take 2 days but i won't be able to commit much time on this today, will be able to have it completed by tomorrow.
If you require anything from my side kindly let me know. I am looking forward to your reply.
Cheers,
Harisankar P S.