Lylo I might move the Braumeister sparge question to another thread if thats ok with you.
PP, you are dead right that I am getting great information here, I am enjoying the answers to my questions as well as digging up past info.
Being new and keen to brew, I think it is not so much info overload that is the problem, as with other industries where advice is given to a DIY practitioner, its the conflicting info that compounds the problems. Possibly doubly compounded by people who think the traditional way is the only way and you end up with novices running around not knowing what to do when all you want is some decent advice.
I have read the sweet liquor shop threads, and I have had discussions with you and others about the merits of Maxi-BIAB in the past, the learnings from those are what started me thinking on this one after I had entered the receipe and realise it didnt work

In essence I want to produce 50L VIF of high gravity sweet liquor in my single urn (Braumeister), in a single mash. 50L VIF is what the urn can produce but at what OG? Having looked at it again with these extra posts I think I know alot more now that I did then

If I am right, the limitations on water and grain 'volumes' in my urn, dictate that I cant do what I want unless I compromise.
Compromise options:
Lower OG expectations - probably best approach as I get benefits and ease of full BIAB - being a novice this will allow me to focus on the process and ingredients.

Lower VIF - lest favourite option for me as it wont go round

Water added B4/During the boil - just doesn't seem to work, grain volume increases and mash volume is all over the place - not an option
Water added as a sparge - helps to reduce mash volume but does not reduce the grain volume - again not helping

Therefore the BIABacus is giving me great info and I hope I'm beginning to understand.
Cheers