So how does these spells look for the initial recognition of 'proto-vis'?
Maximillian’s divinination of the Proto-Vis
InVi 25
By plunging his hand into, or touching a magically tainted object a magus can determine if it can be refined into true Vis. This does not provide any additional information such as how to process it, only noting that it contains the quintescence of Vis. It is primarily used to identify renewable Vis sources which are not, in their natural state, true Vis; but can be processed into such. If the object contains these elements the mage will feel a brief shudder and the hairs on his arm will stand up. His eyes will also flash white briefly, a legacy of the creators sigil.
(Base 4 ("judge the amount of vis present"), +1 Touch, +1 Mom, +2 Group, +1 Complexity)
Maximillian’s enhanced divinination of the Proto-Vis
InVi 35
Much like the junior version of the spell this one will detect proto vis within earshot. This proto vis source will call out resonating tones to which all can hear, and hopefully follow. Like the original the eyes of the magus will flash briefly.
(Base 4 ("judge the amount of vis present"), +3 Hear, +1 Conc, +2 Group, +1 Complexity)
Hmmm i might be tempted to suggest that since you are seeking to detect proto-vis and not actual vis, you could get away with a base 1 "Detect the presence of vis as concentrated magic" since prior to processing you wouldnt really have a quantitative amount of actual vis to discern using the Base 4 guideline.
Thus your initial determination spell would only need be level 10. Could even arguably bring it down to level 5 by making the Target: Part (since it is only the magical essence of whatever you are testing that you are seeking to determine.
Once you have that knowledge you could use Base 4 to determine quantifiable amounts if you so wish, but still at Target: Part IMO, so you would only require a level 20 in that case. Both much more easily created and cast.
Hmm yeah I like that idea. It seems both fair, and of course its always nice to be able to bring down the spell level. Particularly because it means you can easily 'busk' it... i.e. spontaneous magik.
Carrying the principle forward. Using basically the same principles as for developing the spells. Does it seem fair then to require an Rego Vim lab total to work out the precise manner to reprocess it to complrehensive Vim; in the same manner as gather the essence of the beast. Aritrarily assigning a base of 1, seeing as 10 is to do so without a lab we still get only a small value: 4. 1 base +1touch, +2 group.
So I ws wondering, is it ok to insist experimentation is madatory as thisis always new? or again is that too harsh.
hmm well since it is merely a concentration of magical energy that you will have to process to actually arrive at vis, Id say experimentation could well be ruled as essential and would certainly add flavour to what is otherwise a rather bland mechanical/numerical exercise.
On the other hand, remember that experimentation is fraught with its own array of niggling risks, albeit significantly moderated by the very low magnitudes involved in this particular process.
I would again, however, enjoin you to view the Target as "Part" rather than Group, both for logical consistency as well as magical efficiency.
And yet again "on the other hand", (duality of thought becoming glaringly obvious at this point) 
... The base level 10 means more than just not necessarily needing a lab, it means that one can actually concentrate the magical essence that IS vis into a readily portable medium EVEN WHEN no lab is close to hand (out on an adventure for example). Thus given that your "proto-vis" is likely to be discovered and ascertained away from the covenant, your magus would still need to gather the actual distillable proto-essence from whatever its original medium happened to be (strange lake, glowing cave wall, etc) to bring back to the lab to be processed.
For this one WOULD IMO have to stick to the base 10 and come up with a formula like:
Extricate the Eldrich Energy
ReVi(Form) Lvl 20
Transfers an SG determined amount of pre-processed proto-vis energy from a non-portable medium to a portable one without requiring a lab. The vis subsequently derived from this energy will be specific to the form as determined by the original medium from whence the energy was drawn.
Base 10, +1 Touch, +1 Part
Now armed with this I would suggest that the magus would then have to go back to his/her lab and either develop a workable distillation process (the first time round anyways) or use the process developed through previous experimentation to condense the raw energy into usable vis.
Whatever the case, Id say that this route to vis should logically result in a limited amount of actual vis calculated at 1 pawn of vis for every 5 pawns of proto-vis (or 10 pawns of proto-vis if you desire to be more restrictive) since you are, in effect, distilling it down.
First off, if you're worried about being "too harsh", we're going to have to look at your SG license very closely... 
If it's their only source, or every source requires this, then yes, a bit rough. But if it's optional gravy on top of existing "adequate" sources (?), then it's a decision that the PC's can either embrace or reject, their choice (? - depends how they view "adequate", and so on.)
But I'm assuming there will be proto-vis as well as regular, and so it won't be every source that requires this. (If it is, then see 1st line of above paragraph.)
Found an exemple of proto-vis in LatL, p36 (St Malo)
This frankly poses again the question of "How did a magus discover this????"