rear brake caliper options, somehow it always gets complicated Options

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The short version.

I just want to check to be sure that the bolt spacing on 914 rear calipers is the same as early (we'll say '65-73 or so) 911.

Thanks for your help.

Kelly

The long version.

I have '69E front struts and brakes. They were very cheap and work great. I am currently using them with 914-6 rear rotors (yes the car is 5 bolt) and 914-4 rear calipers. I have an adjustable bias valve.
My problem is I used to have a nice bias adustment range with the stock 4 cylinder brakes. Now the bias, even with the valve closed or removed is OK for the street, but I like a little more rear bias for autocross. Yes I realize you can get yourself into a mess in a hurry this way. I would also like to go to wider tires on the rear than in the front and my experience is this will make my bias problems worse.
The solution I'm looking at is using '69 911T/912 rear calipers. These have the larger pad area to match my '69E fronts, but will allow the use of my solid 914-6 rear rotors. It also means that I could swap back to my 914-4 rear calipers to use my e-brake when driving on the street if necessary. This is important to me as I drive the car all summer, everyday and I may need an e-brake if inspection laws change. I would also avoid having to turn down '69 and up vented rear rotors to the 286mm diameter. I have read elsewhere on the forum vented rear disks aren't necessary with a small six like my 2.0E.

Who out there has done this conversion? Anything I am missing?

Thanks for your help.

Kelly