The phrase "available to vary" is correct and usable in written English.
It can be used when discussing options or conditions that can be changed or adjusted.
Example: "The terms of the agreement are available to vary based on the needs of both parties."
Alternatives: "subject to change" or "open to modification".
The amounts available tend to vary between £300 and £3,000 a year.
On the other hand, a number of mechanisms are available to temporally vary axonal conduction and are listed in the Introduction section.
Many universities have training programs in population modeling, but the curriculum content and hands-on experience available to students vary substantially.
Whenever data on other types of relevant contacts are available (availability is likely to vary between countries) and there is knowledge about potential bias in the raw data, these can be added to the dataset and included in EpiContactTrace analysis.
This may occur in survey data but is unlikely to occur, systematically, in GBS data; the probability of a marker read being available is unlikely to vary systematically across individuals.
Learning hours available to prisoners varied wildly - anything from 14 to 95 a year, with "no discernible pattern to the spread of provision".
Despite solid legal underpinnings the medical citizenship actually available to individuals varies widely and depends upon a range of variables.
Available to SSP, SMP Topic to vary each time course is given.
MDT uses the change in crack surface area to vary the available energy per unit area for crack growth and thus to bound the interfacial fracture toughness.
When per-core frequency scaling is not available, turbo boost enables cores to vary their frequency during a computation; the boost is only for a short duration for now to avoid overheating.
