ClassicCar

Morning all,
I'm a bit unhappy and perplexed with my results from my "T" seal install on my 29 Sedan Model R windshield. LAst week I cleaned it up and had the glass replaced. As typical they RTV'd it in even though I supplied them with the channel gasket and "T" seal. So that left me to install the "T" seal. After a few head scratches at trying to feed it into the channel from one side, 4" was the best I could push, pull it in. I used a dull chisel, a rubber mallet and a bit of dish soap and that was successful. Now the bottom 2 ends where the side and curved bottom meet I had to cut the ends. Trying to miter them is almost impossible and after trying RTV to join without success I believe something's wrong with the way I believe it should install. I have nothing to go by here as the original was long gone. So a pic of what the side to bottom joint looks like done right or a little experienced explaination on a how to would be very gratefully accepted.
Thanks in advance
Jack