Any tips for a decent one?

Running a 2.1 with a turbo and the crank case pressure is blowing out of the dipstick hole despite having 1/2 breathers on the rockers. a feed from the blanked off fuel pump fitting (running electric fuel pump) and all into a CSP tower breather, Even got a 1/2 pipe going to the airfilter to help drag it into the airfilter and a small breather filter to help out if needed. The engine is run in and has great compression.

Only happens at high rev's ( I know, dont rev it!!)

You need to hook a spring from it down to the tinker screw. If you look at most racers they have to do it.

Good point, I do that on my coopers rally car, but its just to stop it jumping out.

It's a CB/Autolinea block so doesnt have the boss coming up from the hole that see on the original AS 41 block's, would that be a issue with the seal? It also threw me on my dipstick level as I am unsure if it now affectively is longer due to the fact it goes further down into the sump?

Any one got any measurements? I have a adjustable VDO one for temp too.

I'd check the level by measuring the amount of oil you put in. If you are running it with a deep sump I'd run at the min point of a normal dipstick.