But I would go for the base number of 15hh.
1	But	but	CCONJ	CC	_	4	cc	4:cc	_
2	I	I	PRON	PRP	Case=Nom|Number=Sing|Person=1|PronType=Prs	4	nsubj	4:nsubj	_
3	would	would	AUX	MD	VerbForm=Fin	4	aux	4:aux	_
4	go	go	VERB	VB	VerbForm=Inf	0	root	0:root	_
5	for	for	ADP	IN	_	8	case	8:case	_
6	the	the	DET	DT	Definite=Def|PronType=Art	8	det	8:det	_
7	base	base	NOUN	NN	Number=Sing	8	compound	8:compound	_
8	number	number	NOUN	NN	Number=Sing	4	obl	4:obl:for	_
9	of	of	ADP	IN	_	11	case	11:case	_
10	15	15	NUM	CD	NumForm=Digit|NumType=Card	11	nummod	11:nummod	SpaceAfter=No
11	hh	hh	NOUN	NNS	Number=Plur	8	nmod	8:nmod:of	SpaceAfter=No
12	.	.	PUNCT	.	_	4	punct	4:punct	_
