Allin on the nut flush and gutshot broadway draw

[Ribbo]

There is no wrong way to play nut low draw nut flush draw apart from checking.

You pot if the pot is small and a big bet will get multiple callers, else you make a smaller bet to coax more along.
You pot if the pot is big since anyone with a piece will call anyway.
You call if someone else pots before you.

Out of position I would be more tempted to make a small bet, which will get callers and hopefully someone from late position will raise. This then gets more dead money in the pot. If you just pot from early then it might make people fold who would otherwise call then fold anyway to the reraise (putting more dead money in the pot).
you are happy shoving no matter how many callers, however you do want more dead money if possible.