While considering your PR status in USA, you need to get a job with the strength of your experience and academic qualifications. Once this issue is finalised, your application for H1 Visa will be processed and ultimately it would be cleared. While living over there, you could look out for another job provided the new employer is ready to absorb you with your existing experience and qualifications. H1 Visa would be processed by the next employer under such a situation. While continuing your job, you can apply for the green card but to have this approval, it might take considerable time.
Hence at this phase, you have to look out for such a job which match your qualifications and experience.
2) In relation to get a PR status in Canada, you would be required to land in a job of this country fulfilling bot qualifications and experience. The government would process your visa and you would be intimated accordingly. While remaining in the job, after sometime, you can apply for PR status as per their existing rules and ultimately your PR status would be accepted.
3) it would not be difficult for you to have got a job of your own interest since there is no dearth of opportunities. Moving to this country for a job is somewhat easy since the government permits the immigrants for grabbing jobs according to the capabilities of the immigrants. However, the favourable situation for you would be to procure a job in advance and then move ahead to this country. In that way, you would be in a secured position.