Those who impose this condition differ as to what sort or degree of access is required, as well as to just what it is to which one must have access of the proper sort.

Those who X differ as to what sort or degree of access is required,… The

group of people who favor X have different opinions on what access is required. Somne say more and less and some say less. Some say access, some say each other’s access.

I must have access to… as well as to what it is to which one

must already have access. The same people who favor X also have different opinions about what people must be granted access to. And I know that many people I can know that I do, have contacted but I hardly know where I am. Some say it must be access to Y, others say access to Z.

Yes the original sentence is complex, but see what a lot of meaning it packs in. Two different disputes on related topics and debates among sub-groups of a single group. I wopuld leave out the “to” in ” as well as to ” but I can’t say that it is wrong to leave it in.

I would say, by the way, that the first “as to” serves as the object of the verb differ. It shows, or introduces, the clause that shows, what they differ about. Saying “as well as to” implies a resue of the verb differ with the same subject but a different object, because there is a second difference of opinion among the same group of

people.

Either of these is perfectly acceptable, and there is no significant difference in meaning.

“The contribution is gerund form X” and “The contribution is infinitive form X” should be interchangeable for any verb and any value of X, without significant difference in meaning.