My own alternative would be to do nothing until there is an unambiguous and immediate objective that clearly helps establish a stable future for the club. Until the overall recovery strategy is known, it is disingenuous to ask fans to support it.
However, if the idea is to provide funds to help the club through administration, first accept this may be like opening the widow and throwing your roll of oncers in a bottomless pit. But if that is indeed the objective then I'd talk directly to the administrators and agree a transparent plan that money donated by supporters would be used for specific and pre-agreed purposes only, with this being confirmed in the management accounts.
If the aim is to build a war chest for use in some future recovery package then I would first want to see a detailed plan defining the purpose and limits of that use. I would want to be 100% clear who had control over those funds. People must know exactly what their money is to be used for before any request is made for donations.
Pledges I would avoid like the plague. They are always superficial, generally meaningless and open to misinterpretation, which is no doubt why they are the method of choice of the malignant RST. The SaveRangers scheme intended is to give credence to fan ownership - not you and me owning the club but a tiny tinpot group like the RST exercising that ownership on our behalf without any accountability whatsoever. I support the concept of fans being involved but that should be with the club's support by share subscription and at the last time of asking the fans gave the idea a resounding thumbs down. We could do with a supporter rep on the Rangers board but that does not require Â£1 of our money, let alone Â£10m, to achieve it.