Most DIYers think that it hardly makes sense to buy the the right probe right away. Soem of them noticed that it was the wrong decision - the last thing the note in HV applications.
It's okay to build a HV probe for yourself, as Sam Goldwassrs points and the same recipe you give. As long as you have enough HV experience and you *know* where the critical points are, that is okay.
But the OP has spend money for a Tektornix TDS DSO, which is not a cheap instrument. So I guess there he has a little bit of money left to do things right the first time. Keeps him healthy and the scope too.
just my 2cts of opinion, YMMV.