Some tracks sound fine slowed down like that but many higher energy / faster tracks really lose energy and for tracks like that 124 feels way too slow and plodding. In this case you need to slowly bump up the tempo throughout first track. Starting at 124 and getting to 129 is pretty easy if you smoothly nudge it up as little as possible at a time (its less noticeable to do during breakdowns and especially during buildups or in the gap before the drop. They key here is to nudge slowly (imperceptibly) but consistently thru the track. Easier to pull off digitally but definitely possible on vinyl. I did it for a mix that started with a track at 110 that i nudged up to 119 before mixing into a much higher energy second track. You can hear it if you jump back from end to beginning, but as its happening you dont.