Knighty76,
If you do the Medium Speedmax you’ll need the short stem and pads dead center - that will satisfy your Pad X and it’ll be beautiful. Now…with the stock flat bar that comes on it you will be slammed with no (zero) spacers. That gives you your Pad Y of 570 but you can go no lower - unless you acquired the drop bar and then you’d need to use three 5mm spacers to arrive at 570. I can say this: as the majority of triathletes age they increase their Pad Y - said another way - as we get older (say 45+) we want our pads higher so that we don’t have crane our necks as much to look safely up the road. If you went with the Medium and the flat bar that I’m pretty certain comes in the box you’ll ride it slammed as you are fit now. if you want to come up in the future - no problem. If you want to go lower in the future you can buy the drop base bar and you’ll have 15mm to play with.
Regarding the seat tube angle - it’s listed at 80.5 degrees but there’s quite a bit of both clamp slide and rail slide to give you plenty of range.
Ian