Question about proper fittings to use on shower drain

Hello, new to this forum. I am installing a Schluter shower system using a 2" drain. The original drain was 1.5" and between joist bays. Installing the new 2" trap means that I have disconnected the old 2-2-1-1/2" Wye fitting, capped it off and will cut the 2" drain pipe upstream and insert a fitting of some type- either a Combo, or Wye or San-T? Which is code or proper?

Second question is- it is reasonable to use a short radius 90 degree ell like a vent ell immediately after the shower drain which then connects to the trap, or do I need to use a long turn 90 degree or something else. This is important because I will have to cut into a double 2x10 joist some to get the needed clearance for the drain/trap assembly.

BTW, the vent system is retained by using a San-T with Street fitting on the vent side which is 1.5" and is VTR.

Thanks in advance for any assistance!

http://www.schluter.com/media/ShowerBrochure-ENG07.pdf

MP5SDA3...

Normally a p-trap for a shower has a very tight street bend into the weir of the trap.

Most code requires a combo on it's back for venting if horizontal, or if on the vertical, a santee.

Waste and trap are 2"
Vents are 1-1/2"

If the installation is from far enough back, you may notice that the fittings and sizes they used are different.

It sounds like you have a sanitary tee on its back laying horizontal, not right a vent must come off a horitontal drain at least 45 or more vertical and you need a wye like Terry said not a tee. A vent cannot run horizontal under the shower.