What's the best way to do lifetime deals?

I'm finishing up the final touches before I start to share my latest SaaS on all the media channels and really spend a lot of time trying to push it. I've decided I'll try out lifetime deals at the start. But I'm wondering how is the best way to do them is.

Currently, the pricing is:

Entry-level: €10 a month, €100 a year, or the lifetime deal of €99.
Pro-level: €25 a month, €250 a year, or the lifetime deal of €249.

The questions I have are:

Is the pricing right, or should I increase them? I have a feeling I should make the lifetime deal for more than a year.

Should I only offer a one-lifetime deal type on one of the plans? I'm thinking that having a lifetime deal only on the Entry-level would be a good idea.

And should I limit the number of lifetime deals? If I offer both, should there be 10 or 50 of each or just have an overall limit. Or just allow for the maximum number of lifetime deals.

Also, how long should I keep these lifetime deals available for? I personally, want to keep it short but I also think starting the marketing push I'm not going to be seeing much traffic for quite some time and most likely not selling many sales for quite some time. So would limiting it to 1-2 weeks just be a waste of time?

I'm wanting to do a freemium model, does that affect a lifetime deal?

In case it matters:

The SaaS is https://blether.chat and is a GDPR Compliant Live Chat that integrates with Slack.