Ok but some of the questions still stand ie: what size are the frames?

Since you are experienced with road bikes, what size of frame are you comfortable with on the road? Find out the measurements of you fave road bike and try to match it pretty closely, bearing in mind that you can ride a more aggressive position on the track as the races are much shorter.

Fit is king in cycling so you have to start with that, based on a couple of pictures no one here can tell you which bike suits you better, you have to do some of your own research, try out the bikes and make a decision from there.

Find out the size and geometry of your current bikes, and the size and geo of the ones you're looking at, add a little saddle time on top of that and go from there.