simple answer well it depends, in essence in a split game like hi/lo your starting hands should work for both high and lo hands, for example a234 double suited is nice as you have many low possibilities and flushes and straights for the high end of the spectrum. Obv the board has to be cooperative for a low hand to exist so a high hand is always the only gaurentee.
If its only two players left in the pot, chances are if you only have the high it will probably be a split but when talking tournament and you have the nut high just keep potting it anyhow because you will know you are at least getting back what you put (granted you would want to know you have the NUT HIGH and it isn't going to change). If you are by chance talking cash game, then IMO you don't want to be building the pot if only two players because the only person going to profit most of the time is the house due to rake on a split pot leaving you with less money then you started.
Just my thoughts, hate running into split pots when was only two people in the hand and loosing money due to the rake collected from the pot (sometimes knowing before showdown its a split but having to call raises to get to showdown).
Just my thoughts, I don't play the game really just the freerolls
on stars but know the concept and do ok with them. Would rather poke my eyes out then to play alot of split games though lol.