It would have to be quite a bit cooler before I would consider wearing any leather glove. Around here mesh is the way to go for a good 4 months out of the year. For that I only go with the nylon gloves. As much protection as leather? No, but when it is in the upper 90's to the 100's it is the only way to go. Really when I have to wear my mesh jacket, I also have to wear the mesh gloves, otherwise it is just too darn hot.
Yes they are bulky and thick in my opinion, and they are "race gauntlets" which has no use for me. If they work for you that is all that matters, but their price is still beyond outrageous. Not made in the USA either, so I feel even better giving my money to Lee Parks. I am very familiar with the gloves you mentioned, the Iron Pony is just down the road from me and has those exact gloves.
LOL!!! OK... and the bike you ride is made where? LOL!!!
Too bad you don't have the humidity we do. I wear my GP Pros all the time. They are vented.