The hourglass would probably too drtying if you are just oily in your T-Zone. If your not already using a setting powder I love the HD powder from MUFE I suggest you try that. Hope this helps!
I personally switch my foundation for summer to Hourglass Immaculate that stuff is awesome, you should get a sample... I love that stuff! Its really matte so there is no shine, I put it on at 8am and take off til about 10pm and my face still looks matte, no shine
Two of my fav foundations happen to be full coverage I'd suggest giving the Kat Von D Lock-It Foundation or the Tarte Maracuja Miracle Foundation 12 Hour Broad Spectrum a try. Both have amazing coverage & rarely need touch ups with my combo oily t-zone
You can also try setting your current foundation with a setting powder or setting spray to extend your wear The NARS Light Reflecting Pressed Setting Powder or the Urban Decay De-Slick Oil Control Makeup Setting Spray would be a nice addition