"wont boost or overvet it"
does that mean no items at all? 
expert or vetpacks (without overvetting) can solve any bo problem


i think if you dont add any items you might have a slight problem spotting max range at 2-3.

since you skip the +2 pot for your BO for a couple lvls
but it'll even out along the way

let say about I use at-level BB1 BO 100vets full experts  can I spot the shells at max range?
Im worried in that I will not see the West/East splash when i use the powerleveled BO. 

if you pick a pot +15 you should be able to powerlvl with no mayor issues up to BB1 stage... you will loose something like 60 to 80 hability points... and you will end up with a BO with stats similar of a Pot +14, so once you class him you could spend a boost to correct this issue.

if you experience problems at BB2 stage with short lines and being unable to spot your shells at max angle you should consider overvet up to 120 vets.

but at the end your BO will be usable, you'll just have to put some extra bucks on it.

and if its not you can allways do a BO reset and made it CV BO ;)

If you're not boosting or over-vetting an at-level will not spot shells and you'll have short guidelines.  Some people with properly classed BOs have trouble at that level so power leveled will be significantly worse.  At higher levels though, you everything will eventually catch up but it will likely be a pain for a while.

I did have this issue a while ago but in case you do it, please report back as I'm curious to see how bad it was ~ or if it worked.