Newbie question about vallejo matt varnish

[ftm2001]

Newbie here from UK just getting back into making models. Im making an old fujimi bf109 I found in the attic as a tester to get me started. As I'm from UK I cannot get hold of the original Klear/Future.
I used vallejo gloss varnish to cover vallejo model air paintwork but didn't really get on with it. It went on the blue underside ok but not the sand coloured top surface. The varnish seemed to fill in panel lines etc and pooled up on surface.
I managed to recover the model and am now at the point of final matt coat which im not looking forward to.
I am wondering has anyone used vallejo acrylic matt varnish 26.518 or vallejo premium acrylic polyurethane matt varnish 62.062? I have both.
What would people recommend out of the two as we are now in lockdown 2 so can't get out?

[PlasticModeller]

I use the premium version its a bit more expensive but its very flat and a very tough finish

[ftm2001]

I use the premium version its a bit more expensive but its very flat and a very tough finish

Do you have to thin it and what psi?

[digger303]

What I was using was Winston and Newton Acrylic Matt, but I can no longer find any over here. It was very good, but you shouldn't have any problems locating.