I lost my sprues for 4 out of 6 droidekas, and on those sprues were the ball modes.

Can I use the transformed model for both modes if I have adequate tokens.

Yes.

Correct. The wheel mode models are optional.

Technically, I think one could use a wheel mode droids a unit. I don't believe there is anything written stating that the standup versions are the only authorized version for a unit.

21 minutes ago, Mokoshkana said:

Technically, I think one could use a wheel mode droids a unit. I don't believe there is anything written stating that the standup versions are the only authorized version for a unit.

I think it would be up to a TO whether to allow it. Personally, I wouldn't, just because the wheel mode model has a much smaller profile, which makes them much easier to hide behind terrain.

Also, it would just be weird.

4 minutes ago, Lochlan said:

I think it would be up to a TO whether to allow it. Personally, I wouldn't, just because the wheel mode model has a much smaller profile, which makes them much easier to hide behind terrain.

Also, it would just be weird.

So if one were put them in wheel mode and use the appropriate models you would disallow because they'd be easier to hide?

1 minute ago, Mokoshkana said:

So if one were put them in wheel mode and use the appropriate models you would disallow because they'd be easier to hide?

They have said they intend them to be easier to hide when in ball mode. The rules state specifically that you can choose to use the standing model and a token to represent the ball mode (because you gain no advantage). It is not stated you can do the opposite. Using the ball model when not in ball mode would be an advantage (in theory) and because the rules are written this way I would have to assume you cannot use the Ball mode in place of the standing one in official games.

11 minutes ago, Draycos said:

They have said they intend them to be easier to hide when in ball mode. The rules state specifically that you can choose to use the standing model and a token to represent the ball mode (because you gain no advantage). It is not stated you can do the opposite. Using the ball model when not in ball mode would be an advantage (in theory) and because the rules are written this way I would have to assume you cannot use the Ball mode in place of the standing one in official games.

Fair points and well said. I use the ball droids model right now as non-leaders in order to field three units so I can get 800 point lists with just two core starters.

11 hours ago, Mokoshkana said:

Technically, I think one could use a wheel mode droids a unit. I don't believe there is anything written stating that the standup versions are the only authorized version for a unit.

The “Wheel Mode” RRG entry actually does specify how and when to use the models:

Players should use the ball-form droideka minis only
when the unit uses the wheel mode keyword and only for
the duration of that round. At the end of the round, any
ball-form droideka minis should be replaced with standing
droideka minis.