The rent deducted cannot exceed the fair market rent.
Leasing/subleasing to yourself will not help lower your SE taxes.
BTW, a "real estate professional" pays SE tax on net profits. It's
non-professional rental real estate holders who can avoid SE taxes.
There are a couple ways to get your SE taxes down. You have 2 options.
First, you could buy the office space & decuct the mortgage interest &
taxes & depreciation on Schedule C. This lowers your net income but
also significantly lowers your cash flow.
Alternatively, you could become an S-corporation. An S-corp *must* pay
its shareholders a 'reasonable' salary for services rendered, &
deducts that salary as a business expense on Form 1120S. The net
profit on the 1120S is passed through to the shareholders via a
Schedule K-1. However, it is taxed as ordinary income & is not subject
to SE taxes. The big audit alert here is that many S-corp shareholders
try to pay themselves a low salary & the IRS calls that fraud. Figure
out the bare minimum you'd have to pay someone else to do your job &
set that as your salary. Take the rest of the profits as ordinary
income. If your net Schedule C income is around $90k, you could
probably pay yourself $50k as salary & take the rest as ordinary
income without fearing an audit. You could not pay yourself $20k
unless you had excellent proof that you could hire someone to do your
job for that much.
If you form an S-corp, you'll need to file the Articles of
Incorporation & "maintain the corporate formalties" every year or the
IRS can challenge your S-corp status. Don't forget to file the
election to be taxed as an S-corp within 60 days of incorporating! The
S-corp also has to file quarterly employment tax returns (Forms 940 &
941) & withhold & remit taxes from your base salary.
You can find a lawyer who will incorporate you for $500-$2500 + filing
fees, or you can get a couple self-help legal books from the library &
file the forms yourself. Another method is to form an LLC under state
laws, then elect to be taxed as a corp (partnership is the default),
then file the S-corp election, an carry on as outlined above.