Thomas,
CHIRP covers 100% of the 210 DCS codes (105 Normal and 105 Inverted) that are available to be supported by the Baofeng UV-5R (and similar) radios.
From what I have been able to learn through some googling in the last few minutes, of the 512 possible combinations of DTCS codes, only 83 are considered standard. Apparently all (or nearly all) of the non-standard DTCS codes collide with standard codes (in other words they are seen in practice as being the same as a standard code).
After taking a look at this "DPL / DCS Information":http://www.onfreq.com/syntorx/dcs.html page, I see that the non-standard +276 +326, -067 and -720 DPL codes all collide with both of the standard +432 and -516 DPL codes.
Although I don't have any radios that are conveniently available that I can program a non-standard DTCS code on (I think I have an AnyTone handheld around here somewhere that can), I did confirm that the information shown on this website is correct. After programming one radio (UV-82) with R-DCS and T-DCS set to D432N (+432) and another radio (UV-82HP) with R-DCS and T-DCS set to D516I (-516), I was able to communicate between both radios as if they are programmed to the same DCS code.
So from this I would be confident that you can program your radio with DTCS set to 432N or 516R and you will be able to access this repeater the same as if you had used +276 or it had used +432 or -516. Regardless of the one you choose, the code transmitted over-the-air is the same.
Jim KC9HI