My iron horse sunday came with 745mm sunline v1 riser bars on it, when I saw the flat bars on CRC for £30 in silver I bought 2 pairs, haven’t decided on the length I will cut them down to yet.
However I now have sunline bars on all three of my bikes, or will have once I can be arsed putting them on the hardtail.
Stems are a hope/boxxer top crown on the sunday, fsa os 115 60mm on the Trek fuel ex 2010 and fsa dh300 70mm on the hardtail.
I think about 720 to 750mm is plenty but if riders want to go larger and they like it, ROCK ON!