The theory states that lump sum (everything at once) performs better, the practice (IMO) is that investing in chunks works better for human psychology.
You’ll feel a lot better if the market tanks after your first investment chunk compared to if you invested everything at once.
OTOH you might have some FOMO if the market takes off like a rocket after your first investment chunk.
Size wize (for chunks) go with what you personally feel comfortable with? Start with 10%, see how it feels being in the market for a couple of months or so, then adjust the chunk size for your next tranche accordingly.
Not sure what the prevailing opinion is, but I feel the closer you are to your desired retirement age, the more it makes sense to pay into pillar 2 – you’ll have no drawdowns whatsoever, a guaranteed (albeit small) return, and tax savings can be significant. Given your description, I would do it. I regret only getting smart about this a couple of years before FIREing.
The only reason maybe not to pay into pillar 2 is when you’re at the start of your career and – if you already know about investing (kind of rare at a young age) – you have a decent chance to make a better return (taking into account taxes) than your pillar 2 given your super long investment horizon.
Oh, and as @SwissMousse has suggested: go with a real broker instead of Swissquote. This has already been debated heavily on the forum, you’ll find the topics easily.