And that is precisely why I suggested the specific alternatives of a Tier 1 FCM's 24 hour execution desk work your orders, or leasing a very capable platform that readily supports all available exchange spreads. TT is not your only option for exchange spreads - CTS T-4 has access to a much broader suite of exchange Spread products than IB (last time I checked) and if all you need is a DOM then at 50 cents a turn capped at $500 what's the downside ? Seriously. I don't get it. Penny wise and pound foolish I say.
Furthermore, you don't want to just swing trade oil calendars. You want to swing trade Brent and gas/oil and heating oil calendars as well. And butterflies. And Condors. And play out in the forward curve where there's some edge.