my company .737ng.1/5/gear down ,15/ 30.and if use flap 40,transition with 25 before 40.
and how we choose between 30 and 40 is usually based on how the Vref IS .
it Vref>140 ,then 40.
i agree with you about F10 ,if you need to slow down but quite far away and do not extend the gear.but the truth is ,so far i havent seen any captains use F10.even though its recomanded to do so in the training manuel.
and i did it a lot on 744.but still .some of the captains would not allow me to .cuz its not in the standard procedure.