Pommels, Switch types, blade tip, and blade wheels
Sorry for not coming back on these sooner.
If you're getting a premium hilt (Bellicose price upwards) then you're choosing from the various pommels that come with that hilt - the Bellicose has two options, the Manticores have two, the Malice has three from memory... Just choose whichever one you like best.
From the Dark Prophecy on downwards, you can choose any in-stock pommel you want to go with your hilt. What strikes your fancy is up to you - the Catalyst and Shock pommels generally go well with the Sentinels and Aeon/Dominixes, for example. I just go for the stock pommels on mine when I get stunt hilts, but if you're getting sound then the vented pommel has a large hole in the bottom and folks don't always care for that. I don't think it's worth the extra $30 to get a specific pommel most of the time, but that's your choice.
Unless you choose otherwise, any hilt you buy will come with the black guarded switch type. Again, it's a matter of personal choice, but most prefer to have at least the non-illuminated AV switch on their hilts - whether in black or silver, it looks smoother and has a lower profile so is easier for handling your hilt. It's a $10-15 premium, from memory, and I'd say it's worth having if within your budget. The illuminated switches look cool, and maybe consider it for your display piece, but on the whole I've gone for non-illuminated on most of mine.
As Akacen says, rounded tips are safer for duelling with. I have a couple of pointed ones, but if you're duelling, go rounded. Maybe try a pointed blade on your display piece?
I always get covertec wheels on my hilts as I have several clips and like having the option to hang them off my belt. For costuming purposes, they're practically a must but otherwise it's an extra $15 or so. I like having them, but they're by no means essential to having a working 'sabre
Hope that helps!
