Q's re Spouse visa case submission Karachi, Pakistan

1. I am intending to submit online application on behalf of my spouse on 6 - 7 April 2019. I will then book an appointment for my spouse to attend VFS centre on 8 April or whenever possible. I understand at the VFS centre, my spouse can submit a current and previous passport and have biometrics done.

I have asked my spouse to courier all other (original and copy) documents i.e., letter of support, marriage certificates to me here in the UK. I will then put them all together making a bundle for both of our documents and submit it to Sheffield.

Can I please ask if this is the case (as above)?

2. From the day of biometric, how many days do I have to submit all documents to HO? I ask as I will be submitting my tax returns on 6 April and it may take few days to receive SA302.

3. I read some applicants were able to submit priority application from Pakistan. Is it still the case? and is it worth it?

4. Lastly, I understand I can make payments for my spouse's visa application and IHS via my AMEX?

I am grateful for your responses as always.