Re: SQL Expert for tuning
SQL tuning takes time... I would suggest a two pronged approach. On one side is a dedicated DBA, you are better off finalizing appropriate database settings as well as hardware side before resorting to individual SQL tuning. Finalize the environment wherein the SQL executes... otherwise, individual SQL tuning efforts may become obsolete requiring you to re-tune the queries... x2 overall effort.
Also if data will increase by x50 then again DBA should take that into account and suggest appropriate architecture (table partitioning... parallel execution... etc). There's also other way of tackling the problem... data retention policy, e.g. why have it grow x50 if you only need recent data.
Also do some computation... individual SQL tuning takes time, you have to make sure that one tuning strategy will not cause other queries to suddenly perform badly. It might be cheaper to just buy additional resources than employ additional people, e.g. you might just need additional memory so pages are cached reducing disk I/O, as well as operating system paging, to improve performance of system.