可能形 => Potential form N4
[可能系「かのうけい」] => Can, be able to, be possible to N4
Can, Should, Must
~のは…ぐらいのものだ => only (emphasis) N1
Limit
くらいの => Approximate~ N3
Emphasis on degree
いつかの ... => Previously N4
Time
…の…ないの => thinking whether or not to do something... N2
Position, perspective
というのは => because N2
…からいいようなものの => It’s a good thing that… this time… N1
Criticize
どのくらい => how long N5
... というのは => It means... N3
Explain
ぐらいのものだ => Only A N1
(Not)only , (Not) even
…ばあいをのぞいて => Except for N2
Exception