A question about defences to Asptro/Astro

A recent hand at the club has encouraged me to ask some questions about how people deal with Asptro/Astro-related interference over 1NT (usually weak).

As a quick reminder, Astro normally means that 2 shows at least 5-4 or 4-5 shape in hearts and a minor; and that 2 shows at least 5-4 or 4-5 shape in spades and any other suit. Whereas in Asptro both of the conventional overcalls can have both majors, with anchoring ("initial showing") to the weaker major.

This post isn't going to be about Lebensohl, or Rubensohl, or even Transfer Lebensohl (though a post about those will come at some point). Initially I just wonder what the following bids should mean.

Your side opens 1NT, LHO overcalls 2 showing spades and another suit. Are the following bid meanings standard in your partnership?

• Double = Value showing, 8+ with interest in penalizing something.
• 2Natural, non-forcing to play.
• 2Natural, 5+ invitational and forcing for one round.

I suspect most people play the double as value-showing, though whether it explicitly has interest in penalizing spades is probably not normal. I also suspect most people play 2 as natural non-forcing. But what does 2 mean? Have you got an agreement with partner that it shows a genuine spade suit with interest in game? Or does it show an invitational hand with hearts? Time for a poll to find the answer: hopefully I give enough possibilities:

What does 2 mean after Astro/Asptro showing at least four spades?

Do try and choose one of the options above if it roughly describes your agreement and give more precise details in comments. I imagine you might play it as a game force, which sometimes has four low spades and four hearts, and will bid 3NT next.