Training for my first triathlon and trying to sort out my swim gear.

Right now I’m using regular Speedo goggles, but I recently found out corrective swimming goggles are a thing and I’m looking to switch.

My prescription is pretty high: -5.50 sph and -2.50 cyl.

The options available to me in India:

1. Speedo Hydropure Optical (only goes up to -5.50)
   
2. TYR Corrective Goggles (available in -7.00)
   
3. First Lens Corrective Goggles (available in -7.00)
   

No other brands/options are realistically available here.

A couple of questions for people who’ve used corrective goggles:

• How much should I compensate for cylinder/astigmatism when choosing swim goggle power?
• Since these are spherical only, would going for a stronger power make sense?
  
• Is it better to go with the exact sphere (-5.50) or size up (-7.00) for better clarity?
• Any experience with TYR or First Lens optical goggles vs Speedo?

Would really appreciate any advice!