Interesting question. It comes down to maximize a bunch of objective functions with different weights for different services. The determination of the weights is somewhat subjective, and one may explore the consequences of various weight scenarios and then decide which pathways to take. 

For me, you may undergo a local survey among stakeholders to prioritize service based on their requirement, in addition some global services such as carbon sequestration can also be taken care of.

there may be various way for prioritise ecosystem services (ESs) in conservation, as 1) First you can do valuation (economic) of those ecosystem services which are playing their role in conservation and based on this monetary value of ecosystem services, you can prioritise. 2) make a list of all the possible ESs, and do a priority survey of the conservation managers (forest officers) and concern researchers who understand ESs. Based on their priority you can do it.

Their may be some more site specific methods.

Speaking from experience of actually having to do this:

It's actually even more complicated, as "supporting services" and "regulating services" are not monolithic, and there may well be tradeoffs within these categories as well as across them.

One thing that makes things simpler, on the other hand, is that even in a well-defined area (e.g. a protected area, as in your example) the areas that are most important for different kinds of services may not be entirely coincident spatially. One subset of the area may be particularly critical for hydrological services, another for biodiversity. So the actual tension may not be as great as you imagine, if you are able to intervene at a high level of granularity. But obviously in some cases the key areas will in fact overlap.

In most cases, however, there is a clear priority in any given case (e.g. preserving hydrological flows in the case of a watershed with significant downstream uses). So in practice we start by prioritizing that, and then ask: how do we modify this plan in order to maximize other services as well? In many cases, minor changes to a plan can bring in quite a few other services.

The other practical consideration is: who is paying? If the financing for the planned activities is coming solely from water users, we are somewhat constrained in incorporating efforts to provide services other than hydrological regulation unless this can be done at minimal costs (in terms of additional expenditure and/or reduction in the expected hydrological benefits). But if we have additional financing sources (e.g. a GEF grant to help conserve biodiversity, or carbon financing) then there is more flexibility in seeking to maximize multiple benefits. Note that it would seem that government financing would be the most flexible, in that the government should seek to maximize social benefits. But in practice governments also often have specific priorities, for political or other reasons. And in practical terms, government financing usually comes from a specific agency (e.g. the Ministry of Environment) and so that agency's priorities, end up taking priority.

Speaking from experience of actually having to do this:

It's actually even more complicated, as "supporting services" and "regulating services" are not monolithic, and there may well be tradeoffs within these categories as well as across them.

One thing that makes things simpler, on the other hand, is that even in a well-defined area (e.g. a protected area, as in your example) the areas that are most important for different kinds of services may not be entirely coincident spatially. One subset of the area may be particularly critical for hydrological services, another for biodiversity. So the actual tension may not be as great as you imagine, if you are able to intervene at a high level of granularity. But obviously in some cases the key areas will in fact overlap.

In most cases, however, there is a clear priority in any given case (e.g. preserving hydrological flows in the case of a watershed with significant downstream uses). So in practice we start by prioritizing that, and then ask: how do we modify this plan in order to maximize other services as well? In many cases, minor changes to a plan can bring in quite a few other services.

The other practical consideration is: who is paying? If the financing for the planned activities is coming solely from water users, we are somewhat constrained in incorporating efforts to provide services other than hydrological regulation unless this can be done at minimal costs (in terms of additional expenditure and/or reduction in the expected hydrological benefits). But if we have additional financing sources (e.g. a GEF grant to help conserve biodiversity, or carbon financing) then there is more flexibility in seeking to maximize multiple benefits. Note that it would seem that government financing would be the most flexible, in that the government should seek to maximize social benefits. But in practice governments also often have specific priorities, for political or other reasons. And in practical terms, government financing usually comes from a specific agency (e.g. the Ministry of Environment) and so that agency's priorities, end up taking priority.