Old thread but shows up in search results, has a bunch of incorrect info, and I did a lot of research about this recently. Here's some accurate information:
1. If you had capital losses in a previous year, you do NOT need Tax Trader Status or MTM election, in order to offset capital gains in the present year, or future years. TTS is only useful to offset ordinary income. TurboTax will confirm this. You don't need a CPA or anything. Just import the TXF from your broker, and TurboTax will take care of it (or TaxACT, or any decent tax software).
2.
GreenTraderTax has a lot of information about TTS, and they do taxes as well. I tried to use them, but they never returned my phone calls and emails though.
3. If you trade Section 1256, you do NOT want Mark To Market election. See
https://traderstatus.com/traders/mark-to-market/commodities-trading/:
Tax Summary of the §475 election for Futures/Commodities/§1256Contracts:
forgo making the election and…
§1256 contracts have a nice long-term gain rate for 60% of gains if §475 M2M is
not elected.

§1256 contracts are limited for deductibility of any trading losses if §475 M2M is
not elected. :-(
make the election and…
§1256 contracts have
no long-term gain rate for 60% of gains if §475 M2M is elected. :-(
§1256 contracts are
not limited for deductibility of any trading losses if §475 M2M is elected.

Old Capital Loss Carryforwards may be trapped on Schedule D if §475 M2M is elected. :-(