A steeper seat tube angle usually corresponds to a shorter top tube length and physical reach. The effective TT length is not dependent on seat tube length as its a horizontal The actual 'reach' measurement is not affected by seat tube angle or length
I would suggest the 50 Kilo would be quite close to the EVO fit wise, that half degree in the seat angle can account for the couple mm difference in TT length, which can easily be adjusted for in saddle positioning, or a different seatpoost or stem at worst. Having said that, I'm not sure on TT bike geometry/fit difference preferences vs road bike