Bath sealant question

[Hercules12]

So I've removed all the old sealant - took me a day because there was a lot of sealant where it has been previously used to fill a large gap.
I don't fancy doing the same and would rather use something first to plug up where the slightly larger gaps are before applying sealant.

Could anyone advise me what the best thing is to use to do this? Would it be the expanding filler stuff or is there something a little easier to use?

Thanks!

You can get what's called a backer rod to fit the gap and silicon over it. Make sure the bath is full of water when you do it and until the silicon has cured.

Thanks, Polter.