Dosing help

I’m looking to start running Tesa alongside Reta which I currently have been on for 10 weeks. My current dosing is 3mg every 5 days. Looking to run Tesa at 1mg daily, 5 days on 2 days off. I’ve seen a lot of research reports, etc., saying once reconstituted to use within 7 days. Well I’m looking at buying 20 or 30mg vile which of course would last either 4 or 6 weeks. Is this okay??